What is your normal printing time with RA4?

[Chan Tran]

What is your normal printing time with RA4? I am trying to determine whether that I am using too low light level thus my printing time is like 50 sec for 8x10 at f/5.6. It doesn't bother me but at this low light level I think most of my color analyzers don't work correctly any more.

 

[Photo Engineer]

For an 8x10 from a 35mm, I use about 12" at f11.

PE

 

[Nick Zentena]

Without pulling out the notebook all I can say is less then 10 seconds normally. About 2stops from wide open.

At least for normal negatives.

 

[reellis67]

Are you printing from 35mm negatives? If so, you may be able to get a mixing chamber designed to work better with smaller negatives than the full sized chambers. I know that Beseler heads have one that is designed to cut times for 35mm and smaller negatives.

- Randy

 

[Photo Engineer]

If you use a 4x5 mixing chamber with a 35mm negative, there is almost a 2 stop difference. If you use a 120 chamber with a 35mm negative, there is about a 1 stop difference when compared to the 35mm chamber.

I have all 3 and have run this experiment.

PE

 

[Tom Kershaw]

If I remember correctly; when I was doing RA-4 printing last year, I had rather short (e.g. 2 second) exposures in many cases. (on a Meopta Magnifax 4a colour with the standard 6x9 mixing chamber).

 

[Sparky]

Not to discourage... but isn't it putting the cart before the horse (or something like that) to discuss exposure times without considering that lightsources vary wildly in intensity?

but anyway - at the color lab I used to use, which had junky LPL's - my 8x10s from 4x5 negs were around 8 sec at f/11. Almost always.

 

[Nick Zentena]

Not to discourage... but isn't it putting the cart before the horse (or something like that) to discuss exposure times without considering that lightsources vary wildly in intensity?
.

Hopefully PE can comment but doesn't RA4 paper start having problems when the exposures get too long?

 

[Sparky]

You mean - that each of the dye-coupled silver layers have different response to reciprocity law failure? Bien sur!

 

[Snapshot]

I've been getting good results with a 4.5" exposure with my enlarger lens set to F8 using 35mm negatives. Seems a little quick but I can't argue with what I've been getting.

 

[Photo Engineer]

The newest Kodak and Fuji papers have just about solved the reciprocity failure. It now works with laser printers and long exposure times, but I'm a creature of habit and like to use a constant time and vary aperature.

Of course exposure varies with negative, but the average for me is 12" at f11. The range would still be 12" but with the aperture varying in half stop or less, increments with a recorded white light density reading for future reference. So, I might have f4 - f16 as a total range, and if I go outside that I go to 6" or 24" and move everything by 1 stop either way.

There is no significant reciprocity between those values at all.

PE

 

[pentaxuser]

Hopefully PE can comment but doesn't RA4 paper start having problems when the exposures get too long?

Mine's usually about 7-1O secs and only that much because I fitted a 75W bulb instead of the 100W.

I was also under the impression that there are problems with longer times but if this is so why do some manuals talk of burning and dodging? Either at less than 10 secs is a little difficult.

Also doesn't the Colourstar 3000 manual mention a way of extending times considerably?

The need for either dodging or burning have been mercifully few with RA4 but on those occasions I have tried, using min aperture and some neutral density, I didn't notice any problems with colour. Maybe my times weren't long enough to produce the problems.

I too would be interested to hear from those withthe knowledge

pentaxuser

 

[Sparky]

Hey PE - any idea what the general beginning of the 'danger zone' for B&W fibre materials is?? I would guess it'd be around the 20-30 second range (where you start dropping onto a non-linear reciprocity)...

 

[reellis67]

If you use a 4x5 mixing chamber with a 35mm negative, there is almost a 2 stop difference. If you use a 120 chamber with a 35mm negative, there is about a 1 stop difference when compared to the 35mm chamber.

I have all 3 and have run this experiment.

PE

I don't want to get off the original post too far, but thanks for posting this info. I have the 23C Dual Dichro S head with the full sized diffuser, but have not been able to test the smaller chamber, so I'm glad to hear that the difference is that small.

- Randy

 

[Nick Zentena]

Also doesn't the Colourstar 3000 manual mention a way of extending times considerably?

There is mention on how to deal with low power enlargers or dense negatives. Basically analyze the colour at wide open and only stop down to get the exposure right.

That's the only section I remember.

 

[Photo Engineer]

The reciprocity of each paper will differ, so I can't really comment. I do know that a lot of work was spent on reciprocity of the Endura emulsions. I know that you can safely expose between laser times (very very short, high intensity) up through about 60" with no significant problem. You may have more problem from the light fluctuations or negative density problems than with the paper, so don't mistake outside influences for paper problems.

Different enlargers may give different results by changing mixer heads. Mine were diffusion types. A condenser type diffusion head would probably have much larger differences between sizes.

Color film and paper are so stable in speed that a color analyzer is probably not needed. A small test print and off you go.

PE

 

[Dave Starr]

Omega D5 with 4x5 mixing chamber, light set to low. F11, 16 seconds.

 

[Stew]

Mine usually print well at f8 for 5 seconds with my LPL D6700 enlarger. This is with 35mm negatives.

Rob.

 

[PHOTOTONE]

In making prints from 5x7 up to 20x24 I have used 5 sec. to 60 second times and not found any reciprocity issues with RA-4 process. I have not used Endura paper though., it is probably even better.

 

[Chan Tran]

I did many things that caused me printing time too long. I have found no ill effect with the long printing time. I use the beseler 4x5 with the 4x5 diffusion chamber. I could get a 35mm one but I think I keep using the 4x5 for more even illumination. I use about 60cc of cyan and that's 2 stops there. I think I would change that to 30cc. I want to make minor exposure adjustment via filter and not aperture. I will use f/5.6 for 8x10 instead of f/8 as I think there isn't much different between the 2 apertures.

 

[nworth]

The RA-4 papers are extremely fast. I think they are too fast. I prefer about a 20 second exposure time, but that is usually difficult or impossible with these papers. I settle for about 10 seconds, and even then I often have to use an ND filter.