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    FAQ or Answers to Frequently Asked Questions                  Section 42
            Please check "root" (faq$txt) file for acknowledgements. 
    This is a file containing answers, tips, hints and guidelines associated 
    with recurring  questions asked by photographers.   If you would like to 
    add a tidbit of knowledge to  this list just send it to   ANDPPH@rit.edu 
    who will gladly add it to this collection. For complete table of content
    send message to   ritphoto@rit.edu   with  FAQ$txt  in the Subject: line
                    These files are available in SECTIONS. 
             This is Section 42 and its contents are listed below.

    42.01  -< How to make a 620 camera take 120 film >-
    42.02  -< Slide Labeling and Archiving Software for Stock Photos >-
    42.03  -< Where do pros buy albums and frames >-
    42.04  -< Star Tracking Platform instructions >-
    42.05  -< Processing Forte B&W films in Kodak developers >-
    42.06  -< Determining lens focal length simply >-
    42.07  -< Where can one get royalty-free background music? >-
    42.08  -< Robot camera company address >-
    42.09  -< Split Grade Printing by Max Ferguson >-
    42.10  -< Guide Number when flashes are combined >-
    42.11  -< Some places that process Super-8 motion picture film >-
    42.12  -< Bulkfilm loading without a loader >-
    42.13  -< How do flashbulbs work? >-
    42.14  -< Tripod Tips >-
    42.15  -< Some chit chat on camera lenses used for UV photography >- 

42.01          -< How to make a 620 camera take 120 film >-
> I keep running into cameras that take 620 size film. I believe this is the
same width as 120 film. Is it possible to use 120 film in a 620 camera?
All you have to do to use 120 film in a 620 camera is the following (which I
have done many times):
1. Get a few extra 620 spools. This is the hardest part, trust me. I recommend
   going to garage sales and buying up Duaflexes and Brownies.
2. Get a dark bag and a roll of 120.
3. Put the 120 and 2 620 spools in the dark bag.
4. Pass #1... put the tongue of the leader into the slot in one of the 620
   spools. Keeping the film fairly tight (but not stretching or cinching) and
   making sure the spools are parallel, roll from the 120 spool to the 620.
5. Pass #2... backwards. Put the tongue of the leader into the slot in the
   other 620 spool. Roll slowly until you feel the end of the film, which will
   separate from the backing paper since it is only taped on at the other end. 
   Try to keep the film and the paper together and tuck the film in so that you
   get a smooth roll. Keep rolling until you get to the other end. Unless you
   have done a perfect job (it happens) you will need to gently lift the film,
   tape and all, off the backing paper and move the tape a little to flatten out
   the little "hump" that was created by the rolling process.
6. Now finish rolling, seal with a rubber band, and shoot like normal 620 film!
7. BTW, if you don't process your own film, you should roll it back onto the 
   120 spool (do both passes!) for 2 reasons:
   a. The processor will think it's a normal roll and won't get confused or 
      charge you extra.
   b. If you give your precious 620 spool to a lab, you will never see it again.

Have fun!
Peter Conrad 

Respooling/despooling 120 film onto 620 spools seems a bit awkward to me. I am
sitting here looking at two empty film spools - one a 620 spool, the other a
120 spool. The mechanical difference is obvious - the 120 drive slots are
slightly more than twice the size of the 620 drive slots.
If I recall correctly (going back years to when I used a Medalist in high
school) - many cameras designed to use 620 film, including the Medalist series,
can be converted permanently to use 120 film by simply removing the winding
knob and 620 - size drive lug and replacing the drive lug with one that will
fit the 120 spool. This 120 sized lug can be easily filed out of a scrap piece
of brass or hard plastic. The holding pin on the other side of the film bay can
be built up by using a short length of brass or hard plastic tubing and
epoxying it place.
I know of many Medalists (and other cameras) that were converted by camera
repairmen and competent hobbyists to use the 120 spools. 
There are two caveats here: One, make sure the film bay has enough clearance
to hold the full 120 spool, two - if the winding knob is a press fit rather
than a screw together assembly, a bit more engineering may be called for in
re-assembly. Press fits may not go back together smoothly. 
In any case, many of the 620/120 conversions can be done quickly, cheaply, and
most important of all, permanently.
Marvin Soloff 
Regarding the 620-120 conversions that we have been talking about--You should
be aware that not only are the end pins/drive assemblies different (which is
easy to correct), but also the spool diameters and length are just slightly
different. The old yellow father made the 620 spool just enough smaller so
that in most, if not all, cameras of Kodak design the 120 film spool will not
fit into the film chamber regardless of the end pins. To make the conversion
in these cases involves grinding out the film chamber to accept the larger 120
spool. This task is both difficult to do and usually unsightly.
Kodaks stated purpose for developing the smaller spool was to enable them to
produce smaller cameras. It should be obvious to anyone (due to the extremely
minor dimension changes) that this is nonsense. It is my opinion that this was
just done to protect Kodaks US camera market while still allowing them to sell
film overseas by putting it on different (ie 120) spools.
Ernie Willson 

Sure, you can convert a 620 camera to 120. Three problems.
1. The 120 spool's plastic "wheels" are of a thicker material and a wider
   diameter, meaning that you must enlarge the inside of the camera. This can be
   difficult and destructive.
2. If the camera is a classic, it might be better to keep it as original as
3. It's cheap to respool 120 onto 620. It might not be as cheap to modify the
   camera itself.
Actually, to tell the truth, I don't use 620 anymore. Pretty much any camera
that I find to be any good is also available in 120. So I get the 120 version.
However, if I found something that was a whole lot cheaper in 620 than in 120
for the same camera, I would change my tune.
Peter Conrad 

42.02     -< Slide Labeling and Archiving Software for Stock Photos >-
>I'd like to begin shooting stock photos and was wondering if there was any
>slide labeling software or archiving software for the Macintosh platform.
Yep, there is one, at least. It's called The Cradoc CaptionWriter from Perfect
Niche Software, Inc., 6962 E First Ave. Suite 103, Scottsdale, AZ 85251, tel:
(602)945-2001, fax: (602)949-1707. I think it works, and it's not expensive.
Txiki GuillŽn 
You can order the label material from United Label and setup a template in
Stickey Label (also avaialable from United Label) for printing.  It is best to
layout the label design in Excel or some other sort of database program like
Filemaker Pro first. Then simply import the data into Stickey and instant
Red Bradley  
Image Innovations Inc. has a program called QUICKSTOCK - labels, inventory
records, compiles catalog sheets, generates shipping memos, invoices etc. Call
for free catalog (800)345-4118 Standard disclaimer: I have no affilitation with
this company.
Greg Tims 

42.03           -< Where do pros buy albums and frames >-
I am looking for the phone numberor address of The Michael Co. one of many
photo supply houses in the USA. They supply albums, folios, frames etc. to
portrait photographers and others. Any info would be greatly appreciated.
The Michel Co. (no "a") is at 1-800-621-6649.
Address is 4664 Pulaski Road, Chicago, IL 60630
John D. Thompson" 
For wedding albums I use Capri Album Company located in Mount Vernon, NY 
Phone # is (800) 666-2093 or Ideal Binder Company in Brooklyn Phone# is (718)
Michael Connolly - mikelights@juno.com 
42.04     -< Star Tracking Platform instructions >-
Star Tracking Platform instructions
Andrew Davidhazy, andpph@rit.edu
After putting the file below together I decided to just post it to the list
instead of sending only to individuals. Hopefully there is something here that
will be "food for thought" at a variety of levels! Anyway, the file below
includes several observations regarding making photographs of stars and a brief
outline of how to make a "leaf" type star tracker mount (an improvisation for
an equatorial telescope or camera mount)
In order to make photographs of the stars so that they do not show significant
"trailing" due to the rotation of the earth, it is necessary to counterrotate
the camera along an axis parallel to that of Earth and at such a rate that it
just matches that of our planet.
Trailing can become evident with even such short exposure times as a few
seconds and this effect can be used to great advantage when making images of
the starts that actually exploit the Earth's rotation to show how all the stars
appear to rotate around a point very close to the North star (Polaris). One
simply points the camera, attached to a firm tripod, towards the north and
aims up by an angle approximately equal to the latitude of one's location.
This will place the North star roughly in the center of the camera's
viewfinder. By opening the camera's shutter for a few minutes (or hours if the
sky is really dark) one will easily see concentric circles surrounding the
image of Polaris. Measuring the angle that any one segment of a circle includes
and dividing by 15 degrees will indicate the exact time that the camera's
shutter was held open.
It is interesting to note that the density of any given line associated with a
particular star will not increase much beyond a certain point. This is due to
the fact that the exposure time for the star "trail" is not governed by the
time the shutter was open at all but by the rate at which the image of the
star moves across the film.
Anyway, a simple way to make a device that for all intents and purposes
overcomes the Earth's rotation is illustrated below. It essentially consists of
two "pages" or "doors" with a common hinge which is aimed at the North star and
which can be separated from each other at a particular rate (essentially 15
degrees per hour!) and with one "page" of the device attached to a tripod while
a camera-carrying ball-head or pan-tilt head is attached to the other.
So, make the pages out of good, stiff wood. 3/4 inch plywood is fine.
    <----------- 12 " --------->  <------- 12" ------------>
                                 <-------- 11.46" ------->
    .__________________________.  .________________________ .  
    |                        .--..--.                       |  ^
    |                        |__||__|                       |  |
    |                          |  |                         |  |
    |                          |  |                         |  |
    |                X         |  |        X             X  | 8-12"
    |                          |  |                         |  |
    |                          |  |                         |  |
    |                        .--..--.                       |  |
    |                        |__||__|                       |  |
    '--------------------------'  '-------------------------'  v
                      <--- 5"---><--- 5"--->   
    .---------------_.._-----===*===-----.  .----------.  .-.    Tracker in
    |                ||        | |       L..l          L..l |    "open"position
    |________________||________| |________||____________||__|
                 \  1/4" /             1/4 x 20      1/4 x 20
                  | hole|              "T" nut        "T" nut
                  |     |
                  |     |               Tripod      1/4x20 x6"
                  |     | Ball head      gets       bolt  goes
                  |_____| attached     attached     up through
                    | |   to "leaf"   to this nut   this T nut
                   =====                 (both countersunk)
The distance between the center of rotation of the hinges and the center of the
bolt which will cause the two leaves to separate must be very close to 11.46
inches otherwise the tracking rate will not be as accurately as possible the
required rate.
Onto 6" stove bolt (these have round heads) one attaches a "handle" that one
can turn at the rate of one revolution per minute. A 3" wooden disk, with a 1/4
inch hole drilled into center and held onto or "clamped" between nuts threaded
above and below onto the bolt's shaft works quite well. If the disc is marked
off in 1/12 segments then the time to make each arrive at a fixed reference
mark is 5 seconds. If simply divided into quarters, then the time is 15 seconds
per quarter.                               
              ./ \   Camera attached to
               \  \  ball head and pointed
                \ /    in any desired direction
                 | |                                         
        |_______________________|             Make sure hinge is on your    
        0___________________===_.             left side.         
                 ===         |                Use tripod's pan-tilt head to
                 / \         |                point the hinges towards the
                /   \      ==+==              North or "pole" star.
               /     \       |
              /       \                       Turning 1/4x20x6 bolt once per
             /         \                      minute separates the "leaves"
            /           \                     at the required rate of 1/4
           /             \                    degree per minute!
Let me know if these instructions are not clear enough, if there are errors in
it or if you need further assistance!
comments received from others regarding construction of a book-type tracker:
>Having built one of these (a "book" type start tracker) a few years ago, there
>are a few adaptations that worked well for me. First, depending on the weight 
>of the ball head, camera and lens you decide to use, it may help to use a 
>little epoxy when hammering  the T-nut into the bottom. Didn't take long 
>before mine loosened up.
This problem is avoided if you "hammer" the T nut into the top of the bottom
leaf rather than its bottom. That way the "pulling" action of the tripod threads
locks the bottom of the tracker onto the tripod head. If attached the "wrong"
way you do run the risk of the tracker-plus camera landing on the ground 'cause
all that is holding the T nut in place is friction and the T nut's prongs or
small nails.                                                             
My diagram indicated the T nuts should be installed as I indicated above. In
fact, I made "countersinks" in places where the T nuts were installed so they
would not protrude above the bottom leaf's surface and of such depth that the T
nut's tip would be flush with the bottom surface of the bottom leaf.
>Also, for the turning knob attached to the carriage bolt, it was marked in
>6 degree increments, (ie. divided the circumference into 60 separate
>markings.......one for each second of time). 
nice "touch"!

Andrew Davidhazy - andpph@rit.edu
42.05        -< Processing Forte B&W films in Kodak developers >-
           Processing instructions for FORTE films in Kodak developers
               all times at 68 degrees F, all times in minutes
                       D-76      D-76   1:1   Microdol-X 1:1  HC110 Dil B
35mm films
Fortepan 100           5.25         6.75           12            4.6
Fortepan 200           5.25         6.75           12            4.6
Fortepan 400           7.5          9.25           16            7
120 films
Portrait Pan 100       5.75         7.6            14            5.25
Fortepan 100           5.3          7              12.5          5
Fortepan 200           6            8              14.3          5.5
Fortepan 400           7.60         9.5            16.5          7.3
* Small Tank processing is based on 8 to 16 oz of developer per roll.
* Agitation should be continuous for first minute and then 5 to 7 inversion
  cycles in a  5 second time span every 30 seconds for the remainder of the
  development time.

Hugh Tessendorf - RTesn79923@aol.com

42.06           -< Determining lens focal length simply >-
> I need a method to check the actual focal lengths of view cameras. All
> manufactures stamp approximate values for focal lengths on their lenses. 
> I need a simple method to determine true focal lengths.
The way to do this is to focus the lens at infinity, mark the position of
your focussing standard on the rail (or bed, or whatever), and then rack
out the focus to 1:1. You have to do this accurately; obviously you focus
on a precise rule or something, and then measure the image on your ground
glass with another rule which is also known to be accurate. Mark the
position of your focussing standard again. The distance between the two
marks is your focal length. This works for all lenses that do not have
floating elements.
Henning J. Wulff - henningw@portal.ca 
One simple method is 'Conjugate Positions'.
Set up an illuminated source (such as a sheet of card with a few  pinholes in
it in front of a lamp) and screen, separated by a  distance larger than 4 times
the focal length being measured.
With the lens in the middle there are two positions where the source  is
focussed on the screen, one enlarged, the other diminished.  
          The focal length is given by f=(D^2 -d^2)/4D

where D is the distance between the source and screen, and d is the  distance
the lens is moved between the two focussing positions.
This will covet both thick and thin lenses, as you only measure the  distance
the lens is moved to obtain another focus.  DO NOT REVERSE  THE LENS BETWEEN
If you use several values of D you should always get the same f.
(I cheat with this, I have an optics lab across the passage with  optical
benches to use.)
Jim Thyer 

I am not sure how much precision you need but you can also determine the focal
length of 35mm cameras as well as view cameras as follows:

Place the camera on a table or other support with a piece of paper underneath.
Aim and focus the camera at some distant object and swing it so that the image
is located at one side of the frame. Then, draw a line guided by the bottom of
the camera onto the paper. This marks the orientation of the camera relative to
the paper. Next, turn the camera so the subject is now located on the opposite
side of the frame and draw another line intersecting the first one. Measure the 
the number of degrees you had to turn the camera to make the image move across
the frame. 

The focal length is equal to 1/2 the distance over which the image moved (eg: 
the distance from one side of the frame to the other) divided by the tangent of
1/2 the angle over which the camera was rotated.
The distance over which the image moved may or may not be the full width of the 
groundglass in a view camera. All you need do is to measure the actual distance
over which an image moves as you swing the camera. This distance can be
relatively easily measured on a 4x5 camera's groundglass.

With a 35mm camera you can make the image move from one side of the viewfinder
to the other and either assume this to be 36mm (or a bit less since most
cameras include more at the film than is visible in the finder) or use a screen
that has a precisely ruled grid etched in it with a known grid line spacing and
then swing the camera so that a given image moves from a particular grid line
to another one whose distance from the first one is known.

Andrew Davidhazy, andpph@rit.edu

42.07       -< Where can one get royalty-free background music? >-
> Some where out there is a company that sells tapes that have been programed
> for music for slide shows, background etc. I have lost the information and
> name of the company that sells these. If any one out there has any
> information on where i can purchase tapes to be used as backgraund music?
I have several "royality included in purchase price" cds form an artist named
Gary Lamb. His style is ( & I'm not an educated music critic) is somewhere
between "easy listening" & "new age". The music may be used in whatever
multi media presentations you produce, & is also pretty nice for quieter
studio background music.
I note from the back of one of the cds: 1-800-772-7701 http://www.garylamb.com

I just checked out his website & it has 25 -30 second real audio clips from
his cds, so you don't have to rely on me as your music critic. 

This is worth checking out - try beforeyou buy. I got my cd's at a scholarship
auction during our state professional photographer's convention, so I don't
know what the cost is for "royality included" music but I seem to remember a 3
cd set that most photographers thought was reasonably priced considering you
are allowed unlimited usage.
From: mark - H2oClrPrnt@aol.com
42.08                -< Robot camera company address >-
Someone asked for the address of ROBOT. Here is the teutonic answer:
Robot Foto und Electronic GmbH
Hildener Str. 57
D-40597 Duesseldorf
fon: ++49-211-97 145-0
fax: ++49-211-97 145-31
Christoph Esch - unb702@ibm.rhrz.uni-Bonn.de 

42.09             -< Split Grade Printing by Max Ferguson >-
I had quite a few people requesting a copy of Max Ferguson's article re: Split
Grade Printing. I phoned Ilford and they don't have any back-copies. Instead
of sending photo-copies to all those who asked I hope you don't mind but I'll
copy it out here.
Multigrade printing isn't just all the grades in one box, but also all the
grades on one sheet. Well-known though this fact is, its full implications
aren't always appreciated. I didn't even know them myself until a happy
accident at a summer school I was teaching in Wales some years ago. On that
occasion, a student showed me a print with clear white highlights, so I told
him to go back into the darkroom and burn-in using a lower contrast grade. He
came back with an interesting result that didn't look as if it had been
burned-in locally, so I asked exactly what he'd done. It turned out he'd done
the same as he had before, then given another overall exposure at lower
contrast. The crucial word here is overall. Rather than burning-in separate
areas, he'd burned-in the entire print. It wasn't quite what I'd meant, but
suddenly I realised that this technique had tremendous potential. I went back
to my own darkroom and perfected what I call "split grade printing".
The basic facts of MULTIGRADE printing upon which this technique relies are
two-fold. Firstly, everything that is needed to print all the grades is
contained in every single sheet of MULTIGRADE paper. Secondly, high contrast
grades effect on shadow areas while low contrast grades have greatest effect on
highlight areas. Conventional wisdom says that you should choose the contrast
grade to best suit the negative, with the option to burn-in at other grades if
required. With split grade printing, you choose not one grade but two, allowing
you to print highlights and shadows differently.
Users of fixed grade papers may recognise this idea, which is akin to using
two-bath development. The difference is that split grade printing is more
flexible. When I first started printing, I was putting RC paper through a
processing machine, so all the creative control had to be done under the
enlarger rather than in the development tray. That approach has stuck with me:
I still prefer to work with light rather rather than with chemicals. The beauty
of split grade printing is that it works with everything; MULTIGRADE III and
The test strip is the most important part of split grade printing. Learning to
read it is the hardest skill, and not everybody gets it straightaway. Testing
is done in three stages, though with practice and experience you can usually
skip the first one, which is simply an initial exposure test done on a typical
mid-contrast grade (i.e. 2 or 3). This gives a basic time for the next, and
most important stage. 
Using two different contrast grades (I usually start with 2 and 4), proceed as
follows. Make a normal low grade test going across the paper in one direction.
Choose the exposure times so that one of the middle strips has approximately
normal density. Now, keeping the same piece of paper in the easel, change to
the high grade and make a series of test exposures going across the sheet in
the perpendicular direction, but keeping the very bottom strip marked off
completely so that it has been exposed only by the softer grade. Develop the
print, then dry it off. The result will be an image with a series of squares
that have been exposed with different combinations of the two grades used.
Choose the square that gives the best rendering of highlight and shadow 
detail: that square will correspond to the grade combination that will 
probably give the best final result over the whole image. Sometimes the 
differences between the squares can be very subtle, so look carefully. To make
absolutely certain that you've chosen the best square, do the final stage of
the test. This involves making a print of the entire negative, giving the lower
grade exposure to the whole area. Mask of half the paper, and give the visible
half the second, high grade exposure. Process and dry, then examine to confirm
that the image does work as hoped. Look at the low grade side to check the
highlight details are correct. Look at the double exposure side to ensure both
that the shadow details are right and that the highlights haven't been
degraded. Assuming all is well, make the finished print using the combination
Those are the basics, but there are a few variations and notes that can make
all the difference when putting theory into practice. The first is that
although you can choose any grades you like, it is best to keep them at least
two grades apart. This may sound like a hefty restriction, but it isn't. The
ILFORD below-the-lens MULTIGRADE Filter Kit contains twelve steps, from 00 to
5. If you're treating MULTIGRADE as all the grades in one box, you've got the
equivalent of twelve boxes of paper. But using combinations of contrasts that
are two grades or more apart adds another thirty-six possibilities - three
times as many as in straight single grade printing!
The next important point is that you can't make separate tests of Grade 2 and
Grade 4 and just compare the two prints to choose a happy medium since the
effects of split grade exposures are cumulative. A print that is too soft after
10 seconds at Grade 1, and too hard after 10 seconds at Grade 3, could well
look fine printed for 10 seconds at Grade 2. But giving one sheet of paper 5
seconds at Grade 1 followed by 5 seconds at Grade 3 does NOT give the same
result as 10 seconds at Grade 2. That's the whole beauty of split grade
printing: the results are different to what you get from the use of single
grades alone.
You don't have to test using a basic low grade then adding high contast 
exposures: you can do it the other way around if you think it will work 
better. Times when this is likely are when the negative is a bit thin or the
subject is lacking in contrast. The same principles apply. Try to ensure that
the exposure steps you use are easy to work with (a foot switch on the exposure
timer makes life much easier). 
Split grade printing can be especially useful when making prints for toning.
Highlight details can sometimes bleach out and not return during toning, so it
pays to have plenty of substance in those areas. To help this even more, I make
the prints up to half a stop darker than they would normally be...
... If this all sounds a bit complicated, don't worry. You don't need to 
understand how it works, only how it can be used. Get into the darkroom and
take a couple of tricky negatives with you. Rather than burning-in like crazy,
try using split grade printing. You can still burn-in if you need to, but you
shouldn't have to do anything like as much. And remember, any burning-in can be
done under either high or low contrast filtration. Low contrast will emphasise
highlight detail, while high contrast will mostly increase shadow density
without degrading the highlights. Give it a go. You might be surprised how much
time and effort split grade printing can save you.
Now, if I can provide some anecdotal evidence. One print I was doing literally
took me all day before I was happy. I was very pleased with the result but
relaying the story to Max he suggested I bring the negative to his darkroom the
next day. He printed it in 10 minutes!!! 
Press the link http://www.zynet.co.uk/aperture/Spratt%20Ian/rainboy.html if you
wish to view an example of his split grade printing... OK, OK, it's as much a
plug for me as it is for Max, but then having spent an hour typing this article
out I thought he owed me one.
Happy printing. Regards, Ken Ashby
>>Additional note from Max Ferguson
I've seen a variety of approaches to split grade printing. Some based on Grade 
0 for minimum Gamma then an added exposure on Grade 5 for maximum Gamma, tested 
on 2 seperate sheets of paper.Oooops!A bit limiting.
My test strip is based on Gene Nocon's pre-flash method whereby Gamma could be 
altered to give less toe and shoulder by exposing emulsion to "white light" 
before making an exposure from the negative. This trick was employed by 
cinematographers and also by Ansell Adams.The neat thing was that D-Max and 
D-Min still have the same relationship,ie: Grade 4 remains Grade 4 BUT with an 
extended straight line thereby extending the tonal range.ie; more detail in the 
highlights and also in the shadows.
Gene test-stripped the white light in one direction and the negative at 90ˇ in 
the other direction, giving a checkerboard test strip.The chosen square giving 
a combination of exposures, eg; 2 secs pre-flash plus 12 secs negative. Burning 
in was made subtler without the obvious "hot spot' that can and does occur.
When demonstrating split grade printing I start with Grade 2 and Grade 4 ( the 
old fashioned normal and hard grades ) testing Grade 2 across and Grade 4 up. 
Choosing the right square is the hard bit, (experience helps ). This is 
followed by a second test, checking out that I've chosen the correct exposure, 
the whole image on the low grade followed by half the image on the high grade. 
>From this I can then see if the low grade is correct in grade and exposure and 
if the high grade is adding the right amount of density. The final exposure is 
an adjustment based on the second test. eg: 20 secs grade 1.5 plus 4 seconds 
grade 4.
The squares can also guide the amount of "burn and dodge" eg: Add 5 secs Grade 
1.5 plus 4 secs Grade 4 in the sky. Subtract 3 secs Grade 1.5 1 sec Grade 4 
tree stump lower right corner and so on. Learning to read the test strip is 
very important, I can't teach people to see alas.
I now have an Ilford Multigrade head thanks to Ilford U.K's sponsorship but 
recommend below lens filters, less chance of moving the head when changing 
grades.Colour heads vary, my Leitz Focomat is great, but I've had real problems 
when using LPL's. The main hassle in changing filtration can result in moving 
the head, shielding the paper while enlarger is on to illuminate filter dials 
Colour heads can give you Grade 2 and a little bit, Grade 1 ish etc. If you use 
multiple filtration for Grade selection ( magenta and yellow collectively ) the 
speed between grades remains fairly constant. If magenta or yellow are used 
individually to increase or decrease Grade, neutral density is varied as 
filtration is increased in either direction therefore a variation in paper 
speed will follow. I've found that exposure must be increased, usually double 
for Grades 4.5 and 5.
I usually work 2 or more Grades apart to give 2 discernable Gammas. A box of 
below lens filters gives 12 filter choices, using 2 Grades, (at 2 or more 
apart) will give 36 combinations plus the variation of exposures of each Grade 
will extend this even further. Ilfords Multigrade IV has 3 emulsions, use 'em 
all. Not only all the Grades in 1 box, but all the Grades on 1 sheet, AT THE 
It does take time to get this method on board but it will increase the tonal 
range of your prints. It is particularly useful for toning as you can bleach 
highlights while still hanging on to increased D-Max allowing beautiful split 
tones with selenium - bleach - sepia combinations.
Having established a method, let your now enhanced pallette increase your 
Max Ferguson
Ken D. Ashby - 

42.10          -< Guide Number when flashes are combined >-
>I am using several flashes to light a scene and I need to figure out what the
>guide number is for all of them knowing the guide number for each separately.

The guide number for multiple flashes (at the same location) is computed as
the square root of the sum of the squares of the individual guide numbers.

Thus in your case of GN's of 50, 100, & 120 yield an effective GN of 164.
Robert Shnidman  
42.11      -< Some places that process Super-8 motion picture film >-
>I need an expert of movies to please help me locate an excellent processing
>lab for Super 8 Kodak type G Ektachrome 160 color movie film and Kodak Tri-X
>reversal film 7278.  My source Qualex inc., now states that it does not off any
>services for processing these types of film.  An outfit in Colorado (Rocky
>Mountain) states it will take 4-8 weeks "inhouse" before I receive them.  I'm
>desperate....BFA thesis is due ...soon!

I don't know where you are geographically, but here are a few places to try:
Super 8 Sound
2805 West Magnolia St.
Burbank, CA  91505      818-848-5522
278 Babcock St.
Boston, MA 02215        617-254-7882
Pac Lab Inc.
4 W 4th St.
New York, NY  10012     212-674-8958
Bob Brodsky & Toni Treadway 
(Not a lab, video transfers only, but a great source of info)
Tom Sheft 
42.12            -< Bulkfilm loading without a loader >-
There have been so many inquiries about *How to load bulkfilm w/o loader*,
that I will post the description to the whole list:
I do not use a bulkfilmloader, after I have had some dust in its lips and
ruined a 100 ft. roll of film. I load the cassettes manually in the darkroom,
which has some advantages: You can use different film types at the same time,
saving the money for one or several bulkfilmloaders. You don«t have fogged
frames at the end of each cassette. The procedure is not very difficult, so
most of my students have learnt it in one lesson. This description may seem a
little bit tricky, but often it is more involved to describe a dexterity than
to perform it. The following is a protocol of my personal technique and anybody
is free to modify it.
You need:
1. an absolutely dark and very clean dark room,
2. table with RC surface, 170 cm (Ĺ 5,6 feet) long for easiest handling or
   shorter, winding crank/knob (from an out of use loader or HAMA film leader
3. scissors,
4. reloadable cassettes, tape, bulkfilm.
A 36 exp. film is about 170 cm (5,6 feet) long. Measure off this length at the
front edge of the darkroom table, mark it with a piece of thick gaffer tape at
the beginning and the end. If your desk is shorter measure of half, 85 cm (2,8
feet). These marks are easy to feel in the dark with your middle fingers, while
unrolling the film, holding it with your thumbs and forefingers.

It is very important to open the cassette always in the same way: Hold it with
the spools *crown* upside, so the cassettes slot must face to you on its right
side. Snab off the upper cap and take the spool out.

Put the spool on the table, its *crown* facing you and wind a 3-4 inch piece of
scotch tape 1.5 times round the middle of the spool from the right side. Than
tape the spool on the table one foot in front of you. The *crown* must face you
and the fixing piece of tape must be at the right side. Now arrange the cap and
the empty cassette (in this order) behind the fixed spool in a vertical line on
the table. Repeat this procedure for as many cassettes as you want to load
(start with 3 or 4), taping the spools on the table in a horizontal line and
arranging the caps and cassettes behind them. See picture (;-) below
 I    IL
 I    IL
 I    IL      open cassette, its slot facing the tables surface
 I    IL      on the right side
 oo   oo         cap
   II_______I    --- tape, round the spool, its *crown* facing you
=====================  edge of table
Now arrange the scissors, winding crank and bulkfilm (box closed of course) on
the table, where you will easily find them in the dark, WASH your hands
carefully to avoid finger prints on the film and switch the light off. Open the
box, take the film out of the inner plastic bag, hold the roll of film in your
right hand (left-handers vice versa), take the edges of the film leader between
your right thumb and forefinger (carrier upside, emulsion - facing always to
the center of the roll/spool -  down. With your left hand you feel for the
first spool fixed on the table and quickly remove it. By that the tape will
curl a little bit to the left and you can easily slip the leader of the film
towards the shaft of the spool and fix it with the tape. 

Wind the spool one or two times counter-clockwise and put it into the cassette,
slipping the film through the slot and snab the cab on. To control the correct
fitting turn the cap round one time. Now measure off the right length of the
film by feeling for the gaffer marks at the edge of the table (see above). Do
not touch the film surface. Put the roll on the edge of the table to cut the
film. This is very easy, if you hold the cassette between your left ring finger
and the ball of the thumb, while you take the edges of the film near the roll
between your left thumb and forefinger. 

Open the scissors with your right hand and touch the tip of your left
forefinger with one scissors point below the film. Shut the scissors carefully,
trying to cut the film and not your finger. Now wind the film counter-clockwise
into the cassette with the winding crank attached to the spools crown (NOT
bottom). Do not wind the film leader in, so - AFTER putting the rest of the
bulkfilm back into the plastic bag and box - you can switch the lights on and
trim the leader to its typical shape.
That's it. May be it sounds difficult but after practicing it a couple of times
with some trash film you will reload all your films and spend some big bucks.
Even so at the beginning I would not shoot bulkfilm on weddings.
After loading the cassettes I tape a little label on each, indicating the film
type. After exposure I record date and location on this label. Before
developing these data were transfered to the film by scratching them in the
film leader which is pulled out with the Ilford film leader retriever. (A handy
scratching tool is a common *tile slitter* (?) from a handyman supermarket).
This is a really good aid for archiving the negatives and you can easily assign
a leaking cassette. All the best
Christoph Esch - unb702@IBM.RHRZ.UNI-BONN.de

42.13                -< How do flashbulbs work? >-
>I have seen flashbulbs at garage sales and such. How do they work?
Essentially inside the glass envelope there is a filament of aluminum-magnesium
wire or foil or zirconium based paste in an oxygen atmosphere. These materials
are ignited by a fuse that heats up and burns by the current supplied by a
battery or by a battery/capacitor circuit through the camera's shutter's
synchronization contacts. When the fusible material burns it touches off the
magnesium wire or foil or paste and this then burns producing a brilliant flash
of light. Typically the duration of flashbulb emitted light is in the order of
1/25 to 1/50 second although paste based bulbs may last as little as 1/200
It used to be that before the flashbulbs magnesium powder was used and this had
the rather obnoxious aftereffect of producing a fireball plus associated smoke
cloud ... later smokeless powder was developed.
Flashbulbs produce significantly more light than most electronic flashes
although their light output lasts a lot longer also. The peak intensity of
flash bulbes is typically not as high as that of electronic flash.
Andrew Davidhazy, andpph@rit.edu

42.14                       -< Tripod Tips >-
What to consider when you are looking for a tripod (based on "Living With A 
Tripod", Popular Photography's Photo Information Handbook '95/'96, page 64).
1.- Size
2.- Materials
3.- Heads
4.- Centerpost
5.- Legs
6.- Feet
7.- Features

1.- Size
Consider not only height, but also how much it measures when collapsed (you'll
have to carry it, anyway) and the footprint as well. Weight is related to size
too. the median is seven pounds. Some tripods can fit in a bag, but the extra
leg sections add trouble at set-up time and can be less stable. If you use
camera at the eye level you'll want a tripod that high, but the longer the
extension (of boyh legs and centerpost) the more it becomes unstable, so look
for one that exceeds your own height.
2.- Materials
Wood is beautiful, absorbs vibration and is also a poor thermal conductor (good
for the hands in cold weather).
Aluminium is best if teflon-coated or anodized (both out and inside)
Plastic is the lightest material and some are fiber-reinforced and
3.- Heads
Basically there are two types: ball and pan heads. Ball heads are the most
flexible, but pan heads, specially with long handles, are best recommended for
critical positioning, since you can position the camera with the horizontal,
vertical and tilt movements individually.
Some heads offer camera quick-release, calibrated dial for rotation, stops at
preset angles and bubble levels.
4.- Centerpost
The centerpost is for fine-tuning the camera height without having to deal with
the legs. The more you extend it, the less stability you have.
There are several variations on posts: Some are geared - you use a crank to
adjust the height and lock into place. Some other are smooth, which allows for
easy sliding down and up, but this may be a problem since the camera can crash
down. Some post have a groove so it won't twist, which could damage the gear.
There are also pneumatic posts.
You might like to have a reversing post, so you can lower the camera to ground
level nad in some insances a tilting post can be very useful (such as for
puting the camera against a wall).
Cranks are to be avoided in inexpensibe tripods because they wear fast. Watch
out for open tubes that will allow water and watever inside.
5.- Legs
Take a look at the locks. They should require very litle effort to engage and
they should hold the tripod steady. Avoid knobs that require excesive turning.
There are several types: thumb locks require only one digit to operate and some
are oriented so you must hold the tripod horizontally. Collar locks require a
full grip and should be rubberized. Knob locks press against a small area, so
they might be not too secure. Caliper-style locks, which are also operated with
knobs, offer better locking. There are yoke-level locks which can release all
legs at the same time.
The shape of the legs can tell you things too: U-shaped legs are less strong,
so they must be built of heavier metal. The best legs are extruded -- closed
shapes as seen from one end, such an O or a square. Again, make sure they are
all capped.
6.- Feet
Down to the feet, they can be designed for studio, field, or for both.
Crutch style are adaptable, but can slip due to the small surface area against
a flat floor. Angled feet offer better traction. Ball-In-Socket are great for
even surfaces, adapting for the best surface coverage.
Spikes are exclusive for field work. There are retractable spikes to adapt for
studio or field, but require miltiple turning. Pivoting spikes change easily
from spikes to pad.
7.- Features
Some tripods come with centerbracing. This adds stability by holding the legs
together in relation to the centerpost. There are also locking centerbraces
that will hold the legs steady as you move the tripod around.
Some tripods are designed to reach ground level in the upright position by
extending the legs far away from the center. This may require for special,
short, centerpost.
Some tripods come with handles or allow to adapt a shoulder strap for easy
carrying. Some other come with sealed legs for immersion in water or mud.
There are a lot of other features and accesories for tripods, such as the
ability to extend the centerpost or use it as a monopod and even dollies for
rolling around. These are only the basic guidelines, and I hope they help.
Alberto Tirado 

42.15   -< Some chit chat on camera lenses used for UV photography >- 
> I have been told that when one photographs through a (true) ultraviolet
> filter, such as the Wratten 18A, one must carefully choose the camera lens
> because the large majority of lenses will fluoresce and negate any results.
The bottom line or logic behind a determination of whether to worry about
fluorescence of lens glass or coatings is that if this were the case the light
they would produce would not be image forming light but rather a veiling light 
that would simply cast an overall fog over the focused UV energy (light).
If you are getting recognizable images while shooting through an 18A filter
the conclusion is that regardless of whether the lens or coating fluoresces the
images are _valid_ long-range reflected UV records of the subjects.
> Is there any sort of reference, preferably citable, that shows what range
> the lens glass, lens coating and lens cement does fluoresce?  and hopefully,
> how much light from a standard source, say from the sun, is in the range that
> causes fluoresence as opposed to uv light that doesn't cause the fluoresence?
You don't need it. Since fluorescence is visible (when it is excited by UV and
"glowing" in the visible!) you can proceed several ways to demonstrate the lens
does not fluoresce (but as I mentioned above even if it does the fact you are
making recognizable pictures makes concern about it pointless). One would be to
take it to a science museum where they have mineral exhibits and place the lens
under one of their UV illuminators. If it fluoresces it will glow like one of
the rocks! Another is to use the 18A filter and make yourself a makeshift UV
sample "box" and use the sun as a source. 
                SUNLIGHT FALLS ON TO             EYE      (prevent light from
                     18A  FILTER             //      //    entering box around
                 _____________________      //      //     eye - use a tube)
                |_____________________|    //      //
            ======                   =====//      //====== 
            |                                           |                   
            |     LONG WAVE UV PASSES                   |                   
            |     THRU 18A FILTER                       |                   
            |                                           |     LIGHT TIGHT BOX
            |                                           |                   
            |                                           |                   
            |                                           |
            |        |------------|                     |
            |        |  lens or   |                     |
            |        |   rock     |   (fluorescing rock)|
            |        |------------|                     |
If the rock or the lens fluoresces then it will appear to "glow" in the dark
chamber from which "regular" light has been excluded but into which UV enegry
(light) can enter by way of the 18A filter.
Another interesting thing to do is to coat a piece of glass with fluorescent
paint and place it in the focal plane of the camera. Then, in a darkened room
lock the shutter of the camera a open and set the lens to a large opening and
covered with the 18A filter aim it at a source of light and UV ... (well, only
uv is needed but it is hard to get by itself!). Obviously if you have light and
UV the room can't be totally dark but the idea is to try to keep light from
reaching the fluorescent groundglass as much as possible. Or, just fire an
electronic flash aimed towards the lens in a darkened room. Note that some
flashes have a yellowish UV absorbing coating and these won't work as well for
this demo but there is probably enough uv leaking through that most will work
Anyway, the point of all this is that you should see an image appear on the
glass coated with fluorescent paint! You have made an "image converter"!! Makes
an invisible UV image visible by causing it to excite fluorescence in the
visible which you can see!  truly amazing! 
Andrew Davidhazy - andpph@rit.edu
> I thought this (lens fluorescence) happened below 320nm. Since the 18A only
> transmits down to 340nm or so this lens coating fluorescence should not be a
> major problem, right?
AFAIK it is indeed just the deep-UV that causes problems. My German bible on
IR- and UV-Photography from Guenter Spitzing says this: The shorter the
wavelength, the more materials it will be absorbed by:
- below 330nm it will be absorbed by normal glass lenses
- below 230nm it will be absorbed by gelatine (no film registration possible)
- below 180nm it will be absorbed by ozone (atmosphere) and even Quartz glass
- Between 360 and 313nm the transmission of ordinary glass decreases from 90 
  to 0%.
- The more lens elements, and the more coating, the less UV-transmission. In
  this regard, old, few-element enlarger lenses are recommended.
- Since most glass elements and the cement in them cause slight fluorescence
  effects, contrast decrease can not be ruled out.

- Despite all this, I [Guenter Spitzing] don't want to look at UV-reflex
photography as a too difficult field of photography for ordinary equipment. I
agree with P.W. Dankwortt in his book 'Lumineszenzaufnamen in filtriertem
ultraviolettem Licht', where he says "Our results seem to prove that one can
explore UV-reflex with our basic setup, without special UV-lenses". Much more
difficult is  UV-reflex between 360nm and 235nm; unless using a pinhole camera, 
special lenses are neccessary.
> the metallic coating on the lens fluoresces, etc. 
Non-coated lenses are indeed said to be better.... Yet fluorescence should be
*visible*....at least I believe it should by  definition....can't imagine
fluorescence caused by UV *and* reacting in  UV.
> I keep hearing that it is pointless to even try for pictures without a 
> $4,500 fused quartz Nikor lens.

Why not take a few reference pictures with this film/lens/light(?)  combo, ie a
non-exposed frame, an evenly lit frame-filling object  (known to be
UV-reflective) and a smaller object from the same  material but with a dark
backround (ie a sort of UV-contrast  calibration).
Then there is always the pinhole solution....8-))

From: Willem-Jan Markerink 
=========================== end of section 42 ============================== 
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