About to try my first colour printing.......
Anyone got any tips for my first colour printing? I am using a LPL7700 colour enlarger.
What I am interested in is if there are any simple ways fo calculating exposue change when adjusting filtration?
Also any general hints and tricks will be gratefully appreciated! One that springs to mind - what is the rough "speed" of RA4 paper? is it similar to Ilford MGIV for example? - just so I'm not way out when I start my test strips!
Last edited by Matt5791; 08-09-2006 at 03:56 PM. Click to view previous post history.
Ignore colour filters until you get exposure right.
IIRC using Kodak style filters every 30 is one stop. But that's by sieve like memory. If you go to the Kodak website and search for the docs on one of thier papers it should be in there.
Colour paper tends to be fast.
Get a little hair dryer for your test strips. Get a little notebook. Write down everything. In addition to the notebook write things on the back of test prints. Filters and exposure. Often the next day is when you'll notice what you were doing wrong -)
Every 30cc or 0.30 density of all three color is equal to 1 stop. The magenta is more heavy and the yellow is a bit on the light side.
Color papers tend to be much faster than B&W papers. I once did a test of printing a properly exposed Kodak BW400CN (chromogenic B&W, with orange mask) negative on both conventional B&W and color papers. On my Philips PCS130 with PCS150 control unit, I exposed as follows to get similar results:
- Agfa MCP 310 RC B&W paper: Yellow filtration = 40, magenta filtration = 30, 30s exposure @ f/8.
- Konica A7 color paper: Yellow filtration = 165, magenta filtration = 120, cyan filtration = 55, 15s exposure @ f/8.
To get the B&W exposure time down to 15s, it would be necessary to adjust the filtration to 10/0 rather than 40/30. That'd make for an average of 137.5 cc difference on the yellow and magenta channels (cyan isn't normally used for B&W). At 30cc per stop, that's about a 4.5-stop difference in speed between the Konica A7 RA-4 paper and the Agfa MCP 310 RC paper -- and the Agfa's a pretty fast B&W paper. Looked at another way, with the color paper's filtration settings, you'd need an exposure of between 4 and 8 minutes to get the proper exposure with the Agfa B&W paper. (The contrast would be off, but that's another matter.)
No doubt this analysis wouldn't hold up to rigorous scientific scrutiny, but it should give you a ballpark idea of how fast color papers are compared to B&W papers. Note that the orange mask in color films helps boost exposure times. Nonetheless, I find that I've got to boost my filtration settings up to get at least 2-3 stops of ND filtration for most negatives in order to get reasonable exposure times when making 8x10 prints.
If you can afford it, a dichroic head makes RA-4 Printing much easier.
My Beseler 67-s is amazing.
Sponsored Ad. (Subscribers to APUG have the option to remove this ad.)
Originally Posted by Chan Tran
Sorry to disagree but the magenta filter changes one stop for every 30 filter number change ie. plus 15 magenta will lighten the print by 1/2 stop for colour negative and will darken a cibachrome by 1/2 stop.
The yellow filter has very little affect on density.
As nick says get the density correct first
Pick up a set of Lee colour viewing filters for subtle adjustments.
On the viewing filter cover there is a colour wheel chart and colour mixing chart.
Photo copy this and make it big and place it everywhere in your printing room and memorize it.
If you have the time and energy , do a colour ring around. the process is described in the kodak colour manuals.
A colour ring around mounted in your colour correction area is a very, very valuable tool when starting to print.**This goes for digital printing as well, same principles.*
Your viewing light is important.. here we use tungston, daylight and gallery hot lights. We walk the print under each condition to see the shifts but basically we use a combo of gallery and daylight tungston.
Only use two filters at any given time on the enlarger. If you use three you are only adding nuetral density by the amount of the lower filter number.
Use fresh chemicals whenever you are printing.
It is always ok to ask someone close by what they think of your colour balance, you may be having a bad day and a second set of eyeballs is helpful.
Have fun .
What you say about neutral density is true, but today's color papers are fast enough that you may need neutral density to get reasonable printing times. Of course, this depends on your enlarger, enlargement size, negative density, and so on. I usually need a fair amount of filtration on all three values to get printing times in the 10-30 second range on 8x10 enlargements from 35mm negatives.
Originally Posted by Bob Carnie
Since your color exposure used 3 filters, which is a no-no under normal conditions, you had the equivalent of 110 Y, 65 M and 55 neutral density which cost you 0.55 log E or nearly 2 stops. (1 and 2/3 stops).
Originally Posted by srs5694
Remember, if you use 3 filters it is the equivalent of adding neutral density equal to the cyan filter, and you can subtract the cyan from each of the other two to roughly approximate the new filter pack and then decrease the exposure by the amount of the cyan filter.
You should never use 3 filters for either color or B&W unless you want to use it as a neutral density to increase exposure time.
Matt you might like to consider a Jobo testprinter exposure acetate. It is 10 x 8 so allows for 4 x 4x5 prints of varying filtration. It has 5 strips running across each half of the acetate. Each strip increases density in a linear way. So if you set the exposure to 10 secs then the lightest strip allows for 10 secs and each subsequent one two secs less giving 10 secs to 2 secs. If you'd chosen 8 secs then it would be 8 divided by 5. If you have a varioformat easel then you can do 4 prints at a time at various filtrations.
So one 8 x 10 sheet plus 4 different initial exposure time gives you up to 20 different exposure and 4 combos of filtration. You should be pretty close then.
I've seen it claimed that once you have the correct filtration and exposure for one neg then all the rest should be so close as to be acceptable or only the odd print will require tweaking. However I am sceptical having seen the changes in filtration needed from one neg to another. So without an analyser which is calibrated from the perfect print you have just arrived at, I suspect you could use a lot of paper to get acceptable prints from say 36 negs.
best of luck
Thanks for that everyone.
I'm going to be haveing a go this week (really looking forward to it!) and I'll see what happens.