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03-26-2018, 08:14 AM   #1
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Total newbie, how to set enlarger contrast with a colour head?

I have a new to me Beseler 45 MX enlarger with a Dichro DG colourhead. I've made a few prints with it which has gone really well.... but! I think I can adjust contrast via messing with the filters, but I have no idea what I'm doing (yet). I don't have the manual for the colourhead - it's on order. I was hoping one of you fine folks could tell me, if I want to boost contrast for a print, what should I be doing to these colour knobs?

The alternative is that I buy some contrast filters to go in the drawer that's part of the colour head but... I always try to use what I have first.

The head


2nd print


03-26-2018, 08:22 AM   #2
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This may help:

The DarkroomPrinting Black And White Negatives With A Color Enlarger | Shutterbug

But I'm not an expert and haven't fully read it.

---------- Post added 03-26-18 at 11:28 AM ----------

More info:
Black and White Contrast Control with a Color Enlarger | PHOTRIO
03-26-2018, 08:32 AM   #3
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Yeah, thanks! I was reading it, it sounds like if I dial up more blue light it will increase the contrast, more green, less contrast. Time to expose some more paper. :-)
03-26-2018, 08:34 AM   #4
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QuoteOriginally posted by bobbotron Quote
Yeah, thanks! I was reading it, it sounds like if I dial up more blue light it will increase the contrast, more green, less contrast. Time to expose some more paper. :-)
Assuming you have the right kind of Variable Contrast B&W paper - yes.
It also appears that you need to readjust the exposure after making the adjustments.

03-26-2018, 08:41 AM - 1 Like   #5
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Step one is get variable contrast or polycontrast printing paper which is a special type of B&W paper that varies in contrast with the color of the light.

My vague understanding is that a color enlarger can be used to adjust the paper's contrast but that getting the full range of contrast control requires using the special filters which are more saturated than what a typical color head can produce.

Have fun!!!
03-26-2018, 08:53 AM   #6
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QuoteOriginally posted by UncleVanya Quote
Assuming you have the right kind of Variable Contrast B&W paper - yes.
It also appears that you need to readjust the exposure after making the adjustments.
I'm working with Ilford VC Resin Coated paper.

---------- Post added 03-26-18 at 12:06 PM ----------

QuoteOriginally posted by photoptimist Quote
Step one is get variable contrast or polycontrast printing paper which is a special type of B&W paper that varies in contrast with the color of the light.

My vague understanding is that a color enlarger can be used to adjust the paper's contrast but that getting the full range of contrast control requires using the special filters which are more saturated than what a typical color head can produce.

Have fun!!!
Thanks! I'm using VC RC paper. "Partial Contrast Range" is lots for me. I'm in the "hopeless amateur" stage, at some point I'll be able to decide whether I should get the special filters or whether the colour head is good enough.
03-26-2018, 11:44 AM - 2 Likes   #7
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The contrast is controlled on the magenta-yellow scale. If you want more contrast, add magenta. If you want less contrast, add yellow. Adding either will reduce exposure and you will have to compensate by giving a longer exposure time. If you want to keep exposure times a bit more consistent, then start with both of them at a mid setting and when you increase one, decrease the other. It's actually the difference between the two which gives you the amount of contrast, with roughly 'normal' contrast achieved when you have the same amount of yellow and magenta.
03-26-2018, 12:18 PM   #8
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I haven’t printed in years, but I picked up a full set of Kodak color gels back in the day. I still see them occasionally on eBay for a very reasonable price.

03-28-2018, 10:58 AM   #9
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QuoteOriginally posted by jonby Quote
The contrast is controlled on the magenta-yellow scale. If you want more contrast, add magenta. If you want less contrast, add yellow. Adding either will reduce exposure and you will have to compensate by giving a longer exposure time. If you want to keep exposure times a bit more consistent, then start with both of them at a mid setting and when you increase one, decrease the other. It's actually the difference between the two which gives you the amount of contrast, with roughly 'normal' contrast achieved when you have the same amount of yellow and magenta.
That's a great tip, thanks Johnby! I'll definitely give that a shot.
03-28-2018, 12:24 PM - 1 Like   #10
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You can also use fixed-grade paper. If your print contrast is good for say a #2 or #3 fixed grade paper, then you can be assured you have a good [film] development time for the contrast index of your enlarger.
For variable grade paper, you can dial in your paper grade with the CMY settings. The settings are paper brand/type dependent often. You should check with the data sheet of they paper you are using.

For example, here are some single CMY settings I have next to my enlarger. These are examples for Kodak's Polycontrast paper from years ago.

Code:
GRADE     FILTRATION (C-M-Y)
0 75Y
0.5 50Y
1 25Y
1.5 10Y
2 10M
2.5 25M
3 40M
3.5 55M
4 70M
4.5 120M
5 170M

And for Ilford's Multigrade Paper, these are what you dial in to get a grade noted in their data sheet. There are dual and single settings tables in that link.

Last edited by tuco; 03-28-2018 at 02:12 PM. Reason: Add info
04-04-2018, 04:47 PM   #11
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I'm not interested in color printing, so the only reason I'd own a color head would be for convenience
when printing BW variable contrast paper, avoiding the fuss of placing filters in the drawer.

With practice I'm sure the color head will allow a wider range of adjustment, allowing you to tweak contrast slightly more easily.
That said if your negatives are well-exposed and properly developed you probably won't find the need to do so often.

I always used straight grade paper. 90%+ of the time I could make an acceptable print using #2 paper. Occasionally one would require #3.
I figured anything I couldn't print with those and a little burning and dodging if necessary probably wasn't worth the trouble of trying to save.

I plan to reestablish a working darkroom - albeit a temporary one - in the bathroom of my new place.
This time around I will be using variable contrast paper as well; Ilford MG IV RC Pearl is fine for most anything I'll print.
It will be interesting to see if I can save the type of negatives I had previously written off as unprintable...

Chris

Last edited by ChrisPlatt; 04-04-2018 at 06:30 PM.
04-05-2018, 07:08 PM - 3 Likes   #12
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I wanted to post back here, this has been quite helpful! I was all set to buy some filters before this post, but now I think I'll be good for a while. I have done a few developing sessions, this has worked well.

04-07-2018, 07:06 AM - 1 Like   #13
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QuoteOriginally posted by bobbotron Quote
I wanted to post back here, this has been quite helpful! I was all set to buy some filters before this post, but now I think I'll be good for a while. I have done a few developing sessions, this has worked well.
Great! Iím hoping when I move in a couple of months I will be able to set up my darkroom again! Thereís nothing quite like a wet print black and white.
04-07-2018, 12:42 PM   #14
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QuoteOriginally posted by twilhelm Quote
There’s nothing quite like a wet print black and white.

Wet printing in the darkroom is my favorite part of the photographic process.

Chris
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