Contrast Grades and Colour Heads

Discussion in 'Enlarging' started by mikeg, Dec 21, 2004.

  1. mikeg

    mikeg Member

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    Hello

    I'm slightly confused by the settings recommended for my enlarger for each contrast grade.

    To explain, I have a Kaiser colour enlarger which uses the Durst (max 130M) settings. The Ilford Multigrade RC instructions tell me to use 24Y/42M for grade 3. Now my Kentmere VC Select instructions tell me to use 5Y/50M for grade 3. And another source (Eddie Ephraums excellent book Creative Elements) tell me to use 26Y/60M for grade 3.

    I'm confused!

    These values seem quite different. So, I assume that there is no consistency or standardisation between manufacturers. However, what if I used Ilford Multigrade above or below the lens gel filters? Would filter number 3 only give a true grade 3 with Multigrade paper? Whereas it would give a different grade with Kentmere VC Select?

    Obviously, I will continue to use the settings recommended by the manufacturer for whichever paper I'm using at that moment in time, but it seems odd that the values are so different.

    Anyone able to help me. Enquiring minds wish to know!

    Cheers

    Mike
     
  2. Nick Zentena

    Nick Zentena Member

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    No standard between makers. Worse it's possible none of them are grade #3. ISO standards exists for contrast to I think. But paper makers have tended to label stuff the way they want. You can find info on calibrating your head. You can even calibrate it to ISO standards. OTOH you can just do what looks good and forget the grade numbers.

    Remember the filter is just part of it. The developer might change the contrast a little. The bulb might put out colour a little differently then "normal".

    IMHO forget the numbers. Print what looks good. If that means dialing in more contrast or less then so be it. OTOH if you need to print large numbers of copies then it might pay to calibrate your head and paper.
     
  3. rbarker

    rbarker Member

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    Although I haven't actually researched the matter extensively, it does appear there is a fair amount of variation between both papers and filter sets. It would be helpful if the paper manufacturers would specify which filter set they are referring to (e.g. Kodak vs. Ilford), as well as the enlarger type (e.g. condenser vs. diffusion).
     
  4. mikeg

    mikeg Member

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    Many thanks for the replies.

    I'm getting an RH Design's Analyser Pro for Christmas so over the holidays I'll have a go at calibrating it to my enlarger and paper.

    Cheers

    Mike
     
  5. Tom Stanworth

    Tom Stanworth Member

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    I found a little bit of paper in with a box of paper that had the settings for the major types of colour head. I have so far used it for my Durst and Deveres. The numbers relate to using yellow AND magenta at the same time to give you constant exposure times throughout. It works perfectly. Dialing only yellow or magenta can be used but you dont get constant exposure times. I am a sucker for simplicity and was happy to forgo the approx stop of speed and keep things constant. I do use full yellow or full magenta for burning in sometimes.

    I'll dig it out (I've the relevant numbers taped to my respective heads), but have the original somewhere....

    Tom
     
  6. Neal

    Neal Subscriber

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    Dear Mike,

    May I suggest that you purchase a step wedge and determine your own contrast ranges? It's very easy to do and combined with a cheap exposure meter will get you in the ballpark quickly.

    Neal Wydra
     
  7. Ken N

    Ken N Member

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    I found that my colorhead was not giving me consistent grade control. It was pretty close for Ilford Multigrade RC, but using any other type of paper (including MGIV FB) would skew substantially. I got a set of Ilford filters and it addressed the problem.

    Ken
     
  8. Maine-iac

    Maine-iac Member

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    I have a Beseler Computer Colorhead (purchased new in the late 80's) without the computer control. I use it for all my B&W printing. I discovered early on that not only is there no standardization between different filter manufacturers, each paper responds differently as well. I spent a lot of time initially, working out my own grade equivalents with different filter combinations, posting them on my darkroom wall so that when I switched papers, I'd know what combination of Y and M to use.

    Then I got smart and began using split filter technique for all my printing. For each paper, I have arrived at a basic starting exposure time. Printing has become much easier, plus I have the added benefit of much better local contrast within the tones, so that the tones in the print "sing" more than they did with single-exposure, combined filtration.

    You can establish your basic exposure time for each different paper with two sheets of paper. It won't change thereafter unless you change magnifications. On one sheet, e.g. of 8X10 Agfa MCC 111, set your colorhead at full yellow, your lens at whatever f/stop you prefer, and then give incremental 3-second exposure strips across the whole paper. Repeat with a second sheet only this time set your head for full magenta. Process both sheets, and when you turn on the lights, you'll find the strip that best approximates what you want in both shadows and highlights.

    Let's say that you determine that the best strip on the "yellow" sheet is 6 sec. at full yellow. On the "magenta" sheet, the best strip is 8 seconds at full magenta. This is your basic split filter exposure.

    Now make a print, giving it two exposures--one for 6 sec. at full yellow and the second for 8 sec. at full magenta. (It does not matter which order you do these in--at least I have never noticed a difference in the prints.) Then process and evaluate. You should be very close. If you think it needs a bit more or less of either filter, adjust your time, preferably keeping the proportions between the two as close to the same as possible. (My Beseler darkroom timer permits .1 second adjustments.)

    No matter which negative you're printing, as long as you're using this paper at this magnification, your basic time will remain the same. If your neg is wildly different from the usual, i.e. very over- or under-exposed, the basic time will tell you which direction you have to go to correct it.

    Burning and dodging take a little practice to get your head into the technique with split filters, but once you "get" it, it's dead easy. Increases or decreases in density should be done with both exposures equally. Increases or decreases in contrast should be done with increases or decreases in one or the other exposure. Again, try to keep the proportions between the two exposures reasonably the same as your basic exposure, but you'll quickly see that the added step of turning your dials and doing a second exposure for each print will be well worth the time and paper saved to get to a good final print.

    Larry
     
  9. SuzanneR

    SuzanneR Moderator Staff Member Moderator

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    Larry,

    I just uploaded some photographs I printed using a similar technique in the standard gallery, my first attempts using this method. I followed the instructions in Les McLean's book, and loved the results. My question to you is, do you use this technique with all your negs, or just contrasty ones? Fortunately, I didn't have to dodge or burn anything, which leads me to my next question... do you find that you have to dodge and burn less using split grade printing? And lastly, as I have a color head, I found my soft filtration worked best at 80Y, (grade 0) and full yellow made the soft filter exposures too long, and too different from the 200M (grade 5); do you use the full yellow to standardize for any paper, or do you vary the filtration depending on the paper... if that makes sense??

    Thanks for the informative post, between this and Les' book, I think I'm starting to really understand split grade printing.

    Kind regards,
    Suzanne
     
  10. Les McLean

    Les McLean Subscriber

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    Thanks for the comments about my split grade printing description in the book, I'm pleased that it works for you.

    I produce high contrast negatives as much as I can to accommodate split grade printing but clearly there are times when high contrast will not suit the end result that I visualise. I see that you have settled on 80Y for your soft filtration setting, in my opinion you are just about spot on. I do lots of workshops using different enlargers and when I use a colour head I set it to 70Y for soft filtration, I decided on that setting after carrying out my own tests on several differnt colour head enlargers. I also agree that to use 200Y is simply extending the exposure and gains nothing in the printing.

    Best of luck with your printing, if you need any further advice please PM me and I'll be happy to help.
     
  11. SuzanneR

    SuzanneR Moderator Staff Member Moderator

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    Thank you, Les. I'm going to keep working on this, but I think I'm off to a good start, and may add a little dodging and burning. I'll let you know if I have any trouble.
     
  12. Maine-iac

    Maine-iac Member

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    Suzanne,

    Yes, I use split filter printing for all my negs. Haven't done anything else for 25 years.

    Yes, I do find that I have less burning and dodging to do. I think it's because the separate exposures, each at full settings, actually bring out all the shadow and highlight detail that's in the negative. That said, I still do use burning and dodging frequently, particularly when I have (1) a negative that's not as well-exposed or developed as it should be, and (2) when I want to make deliberate changes to the density or contrast in some part of the image for aesthetic reasons. With most well-exposed negs, the basic M and Y exposures will get you very close on the first try, once you've established your basic printing times for a specific paper.

    I do always give full yellow and full magenta exposures. I can't say why your yellow exposures give you widely varying times from your magenta exposure. May be your colorhead or filtration system is different from mine. I have a Beseler Colorhead. Also, papers vary considerably in what their emulsions require. E.g. Ilford and Forte papers usually want about twice as much magenta as yellow. Agfa times are less widely separated.

    My basic times for Agfa MCC, for example, are

    at 8 X10 size print and f/11 lens setting: 8 sec. full magenta; 6 sec. full yellow.

    at 11 X 14 at f/11: 12 sec M; 9 sec Y

    Of course, this is to produce prints to my subjective taste in contrast and density. Your preferences may be different. I tend to like full information in shadows and highlights, so I tend not to go for a lot of stark blacks or stark whites.

    You may wish to try this in conjunction with a divided developer formula as well. I have an article and formulas in the "Chemistry recipes">"Paper Developers" section if you're interested. I've also used this method of development exclusively for 25 years.

    Larry
     
  13. SuzanneR

    SuzanneR Moderator Staff Member Moderator

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    Thank you Larry, it's great to get advice from people with so much experience. I'm not ready to try the divided developer just yet... one thing at a time! But I think I may employ this technique a lot. It was really easy, and I think you are right about the exposure times. The last neg I printed I didn't do any exposure testing... time was running out, and I had to pick up the kids! Both the other negs I had printed came up with the same times, and that last neg was nearly perfect.

    It's snowing today... no school, so I won't be able to try it again til next week!