Practice makes perfect
Originally Posted by gattu marrudu
BTW if anyone needs the formulas I am using , I defer to Ian Grant who has helped me economise and work from scratch formulas.
He is the man.
And the day Bob will spell or say my name right, cows will fly...!
But for murals listen to Bob.
Which formulas do you use?
Originally Posted by Bob Carnie
For my latest large format project I used Ansco 130 (I get glycin in 500g cuts from Photographer's Formulary when I am in the USA since it looks impossible to find in EU); acetic acid (but I will use citric acid next time! That stuff smells in wide containers); double plain hypo fix (sodium thiosulfate + sodium sulfite - http://www.heylloyd.com/technicl/plain.htm ) and a separate acid fix for test strips so I don't pollute the one reserved for final prints; selenium toner 1+25 OR Agfa Sistan (very useful to get an uniform drying, acts as a wetting agent). Water at each step.
I think this is a pretty economical and effective concotion.
As for the enlarging plane, as Bob suggested, I might use a thick wood board with a steel plate attached, so I can use magnets.
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Would rather keep the final formulae between Bob & myself.
However essentially a PQ Universal type developer, as they are clean working and economic, a Rapid fixer - essential with large images, and a wash aid based on Sodium Sulphite.
1. Take 35mm film and enlarge onto 4x5 film to end up with a 4x5 reversed film interpositive.
2. Take 4x5 film and enlarge onto 8x10 film to end up with a correctly-oriented 8x10 working negative.
3. Take 8x10 working negative to a professional lab and have them print a 4x6 foot print from it.
When you take the 8x10 working negative to them, they will only have to do a 6x enlargement (a tiny bit more, actually).
I suggest litho film and a continuous tone developer that I use called Soemarko's LC-1. This will make the whole stepping up process able to be done in red light (as opposed to total darkness), and will make it much more affordable than using "good" film.
The formula for LC-1 calls for three parts, but in group lab periods, I often mix up a faster-working ready-to-use solution, bypassing the parts. I have come to prefer the convenience of this directly-mixed version. This is my formula for a gallon of the stuff:
1. 3 L water, brought to about 50 C
2. 5 g - 6 g metol
3. 5 g - 6 g hydroquinone
4. 100 g - 120 g sodium sulfite
5. 5 g - 10 g sodium bisulfite (The more you use, the slower the film will achieve contrast. Use more for contrastier negs, and less for flatter negs.)
6. water to make 4 L
- Let cool to room temperature before using.
- Use in a tray in red light.
-Expose for low tones. Develop for high tones. Development time will depend on contrast desired, and can range from 2 minutes to over five minutes depending on negs and contrast desired.
- Pour back used developer from tray into jar.
- Toss and make more when it loses its punch (takes much more than 6 minutes to develop)
Note: Negs will have a warm tone, but this is irrelevant, as they are not the final product.
Make your interpositive of such a contrast that it includes all detail and texture you may wish to incorporate into your final print. For the interpos, too flat - even waaay to flat - is better than too contrasty. The important thing is only to transfer all detail you want to have the option of using. You just need the raw materials for crafting the working negative to be present in the interpos. You can step up your contrast when you make the working neg, and it can again be stepped up when making the print.
When making the working negative, LC-1 may not give you enough contrast for what you want, even with extended development times. If so, there are many other developers you can use. I would start with a dilute form of HC-110, used one shot, and gradually and small amounts of A+B working solution to raise contrast if needed.
Worry more about the contrast on your working negative than on your interpos. It is what the print will be made from. I suggest using contact prints as a rough estimate of contrast required for the print.
"Truth and love are my law and worship. Form and conscience are my manifestation and guide. Nature and peace are my shelter and companions. Order is my attitude. Beauty and perfection are my attack."
- Rob Tyner (1944 - 1991)
A Rodagon G is indispensible for making murals. If you're in perfect alignment there is no reason not to use this lens at wide open. As for holding the paper flat, I find magnet's to be a PITA - the rare earth variety are too strong and the strips not strong enough. Not to mention the fact that you'll have a very hard time getting your enlarging surface planar if you try attaching sheet metal to wood - a perfect plane to project on is essential for critical printing especially when using the optimal f-stops. Instead of magnets, I prefer using 1/8" x 2" x 5' lengths of steel flat bar wrapped in gaffer's tape - so much easier. No need for a vacuum easel either as the natural curl of the paper will lie flat if weighted. Having a flat flat surface to enlarge on makes it easier to keep things sharp when working with small negs- try mdf (you can get it in five foot wide sheets) or even better yet, a sheet of covered aluminum honeycomb from either paneltec or alcore as it's much much lighter (something to consider if, like me, you do not have a commercial drkrm. with a dedicated mural set-up). Different strokes for different folks however I've honed my technique within the constraints of the space I work in. I get tack sharp murals from all formats on paper up to 60" wide so I've never felt the need for internegs. The most important thing to remember before you go mcgyver on this...K.I.S.S.
You may get some further ideas from the work of John Chiara and his Ultra Ultra Large Format camera. Some of his processing work is shown too in this video:
"The nineteenth century began by believing that what was reasonable was true, and it wound up by believing that what it saw a photograph of, was true.
" - William M. Ivins Jr.
"I don't know, maybe we should disinvent color, and we could just shoot Black & White.
" - David Burnett in 1978
"Analog is chemistry + physics, digital is physics + math, which ones did you like most?
Some math (re value of internegative for big enlargement)
35mm to 4x6 feet = about 50x enlargement
f8 on lens = f416
best resolution on your printing paper is going to be about 5 lp/mm
35mm to 8x10 positive film = 7x
f8 on lens = f64
best resolution on internegative = 23 lp/mm
8x10 negative to 4x6 feet = 7x
f8 on lens = f65
best resolution on paper = 23 lp/mm which will just equal what is in the internegative and is better than the DIRECT way. Even if you stop down your 300mm enlarging lens to f11 or f16, you still will be ahead of the direct route.
(nice coincidence that with an 8x10 internegative both steps are about 7x enlargement )