Cibachrome filters for RA4?

[olleorama]

Quick question, won a cibachrome filterset on an auction site for a ridiculous sum (a 1/7th of a dollar...) in hope it could be useful if I venture into RA4 printing in the future. The text didn't say so much except that there were .05-0.5 in all three of C,Y and M.

I'm aware that using a filterbox for colorprinting seems to be a PITA but for this price I can afford to test, rather than to buy a new colorhead.

Useful or not?

 

[lilserenity]

Yes. This is how I started RA4 at home with my B&W Axomat 5. You may need to cut them down for your filter tray but they work fine.

 

[nickandre]

They work fine. the only issue is that you have no more precision than 5 CC, so you may not be able to get perfect color balance. It worked fine for me though.

 

[Mike Wilde]

I printed color for the first 7 years on such a set, until a good deal on a dichroic enlarger found me.

A pocket calculator and a scratch pad will be your friend to help find the corrected times after a filter change once you are happly with the exposure.

I would recommend hunting down a print viewing filter set; it will help you better to judge which change in filtration is required faster than just a ring around poster, although the ones from the old Kodak dataguides are good.

Another good tool to get you better at printing colur is a printing filter matrix ( I think mine is called ektacolor, but there are other brands) that you contact print over the part of an image that you project from the enlarger containing a grey card in the neg. You shoot the grey card to fill half of a frame of 35mm under the light conditions that the balance of the film is being shot under. Then the print is processed and you look at the matrix image and figure out which one gives you good density amd gives you good neutral grey and correct exposure and filtration for the next go around. Once you find the filtration the balance of the roll filtration should be substantially the same.

If you are thinking about RA-4 in the future, I would recommend that you start to standardize on one or two C-41 films now (say one 100 iso and one 400 iso) and one place to get it developed. Then find a way to at least take a shot o fa grey card under daylight and tungsten illumination once or twice with each film type. This will give you a basis to start printing from in the future. The mask color of all films are not created equal, and different places do not all give the same look after development in what is purported to be a standard c-41 development process.

Printing color effectively is all about controlling a multitude of variables. Start early, and by the time you print there will be fewer variables to deal with as you are learning.

 

[olleorama]

I would recommend hunting down a print viewing filter set; it will help you better to judge which change in filtration is required faster than just a ring around poster, although the ones from the old Kodak dataguides are good.
Printing color effectively is all about controlling a multitude of variables. Start early, and by the time you print there will be fewer variables to deal with as you are learning.

I got one today actually!

Are there any recommended online articles or books that are recommended for RA4 printing? Or physical books would be even better. I do know the basics, but as you all know there is always more to it. Apugs forums is fine, but a bit scattered, and frankly, I hate reading from the screen, and the typesetting makes my eyes bleed after a while.

 

[brucemuir]

Mike,
Excellent info, thank you.
I've seen a few devices that look like they might be a printing filter matrix on that famous auction site we all know and love.

Can you post a link to what one looks like and possiby who made them so I can keep my eyes peeled?.

 

[nickandre]

(there was a url link here which no longer exists)

I've heard viewing filters are helpful, and believe they would be, for assessing color corrections. Personally, I find that any color checker in a reference photograph makes it very easy to establish a color balance. It will take you a while to get the color balance thing down. Also, when in doubt over-correct. It's much easier to interpolate than extrapolate.

and avoid fuji papers at all cost.

 

[Mike Wilde]

Apart from my lici colorstar 3000 (oh will I be sad when the time comes that it dies and I can't fix it) the handiest is a ring around. Then the next best tool -

The Kodak Ektacolor FilterFinder Kit. Kodak Publication No. R-30, edition 1, 1978. Old cat # was 102 7408. Mine I got used, and it has the original price of $29.40, which was a lot of coin in the late 70's.

It includes a two page ring around that also appears in other Kodak publications of the era, and a 8x10 grey card, of the same sort that Kodak sold independently for about $30 for two of them at the same time.

There is a dial calculator, much of the sort that shows up in other Kodak darkroom data guides, to help you figure new exposure times at a different head height once you have a good small print, with the exposure correct.

This one also includes corrective scales to help you find the right tiime based on your test tiem if the exposure is judged to be 1/2 stop too light, too dark etc, or the new time if you are adding in new acetate filters to correct color cast. This dial I originaly worked without by using filter factor tables and a scratch pad and pocket calculator.

The real gems of the kit are the last 2 bits - One is a peice of 4x5 transparency film, and the other is a density reference patch.

You photgraph the grey card in the light situation that the print you want to get filtration sort out for, ideally on the same roll, but the same type and speed of film, developed the same way will work lamost as well. (In a pinch without a grey card at hand, I have also used weathered asphalt road paving as a grey reference source and then slightly adjust exposure to suit later.)

You project the grey card image and print though the transparency film which is in contact with the paper on the easel. The transparency has patches of 0-30cc of color in the yellow, magenta and cyan axes. It also has places to encourage you to record what test print number was made, the filtration used to measure it, which of the test squares is closest to grey, and the exposure correction factor.

The locator card has 1/2" square patches of varying degrees from white to black with 18% grey in the center, and two stops away in either direction in half stop increments. Each sqaure has a bit smaller than 1/4" hole punched in the middle of it. They are numbered for the exposure factor: 4 (white), 3, 2, 1.5, 1 (mid grey), 0.75, 0.50, 0.38, 0.25 (balckest) This tool can be made by careful exposure of b&w photographic paper.

You use this tool to judge how dark the test print grey was made though a clear part of the transparency overlay. Say that the grey was 1/2 stop overexposed. Then you use the window in patch of .75 denisty to look for the gery square in the colour varied squares part of the exposure. This allows you to refine the color further without trying to first nail the right denisty perfectlly on the wrong filtration, and hence gets you that much closer on the next iteration.

There is also a stright forward 11 page illustrated booklet on how to use the kit best, and what to do if things are not going well.

If there is interest, I may attempt to clone the transparency as a project over my Christmas holidays. I have a box of about 37 sheets of 4x5 Astia that I consider my evenest transparency film, and may see if a dupe using pre-flashing to control contrast can yeld an acceptible clone that can be measured against the original on my denisitometer.