printing b&w on color head enlargergreenspun.com : LUSENET : Large format photography : One Thread
There is a chart from the enlarger company telling me what color pack to dial in for each filter grade, but the chart also says "it" is only a reference. I was told that +M, more contrast, -M for less. Any advise on printing b&w on a color enlarger?
-- Raven (firstname.lastname@example.org), March 09, 2001
Setting all the filters to zero is pretty close to grade 2. Increasing magenta increases contrast. Increasing yellow decreases contrast. Use one filter or the other. Don't use yellow and magenta at the same time. The chart with the enlarger is a good starting place. Many papers come with a data sheet that includes info on filtration. This too is a good place to start.
If all filters at zero is too contrasty, dial in some yellow, based on the suggestions in one or more of the references. If it's too flat, dial in magenta. It's really pretty easy, and you'll catch on fast.
Don't forget that you need to use multigrade/variable contrast paper.
-- Dave Willis (email@example.com), March 09, 2001.
I agree with Dave. Start at zero filtration, and add M for more contrast, and Y for less.
When I first started using a 45S color head for black and white, I posted the filter equivalents on the wall. Now I ignore them. You quickly develop an intuitive feel for the amount of M or Y you need. I write the filter value on the back of the finished print.
It's not really important to know if you're printing at grade 2 1/2 or that you're using 100 units of magenta. These numbers are arbitrary. It IS important that you know if your print needs more or less contrast!
If you really need to know how the color head corresponds to the mulitcontrast filters, get a 4x5 step negative and print the least dense strip so that you're using the minimum exposure for maximum black. You'll see more or fewer steps depending on the contrast. Do this for all your filters. Then make similar prints with the color head at various settings and see which ones correspond to the ones you made with filters.
My "grade 2" is actually quite soft, so I usually add some M. Your mileage may vary, of course.
-- Kevin Bourque (firstname.lastname@example.org), March 10, 2001.
Raven: Good advice from the previous posters. Don't worry about the numbers published...work from what looks good to you. The beauty of using color filters is that you can get a grade 2 7/16 paper contrast if you need it. Also, the indirect lighting from the color heads gives you the same effect you get from cold light. I use a cold light now, but I used the color heads at work for years and liked them. The main difference is that cold lights are cheaper to buy and keep up. The bulbs for color heads can get to be expensive if you print a lot.
-- Doug Paramore (email@example.com), March 10, 2001.
If you use Ilford or Agfa variable contrast paper the above answers are correct. However, if you use Kodak paper the suggested values are different and you will need to use both yellow and magenta at the same time for some values. If you can find the ownerís manual for a Beseler color head it has a chart for both Ilford and Kodak variable contrast paper. If you canít find one email me and I can send you one. I donít have it at home or I would send you one now.
Joseph A. Dick
-- Joseph A. Dickerson (firstname.lastname@example.org), March 10, 2001.
Joseph, I've been using Polymax II paper on a 45S Dichro head for years, using just magenta to add contrast/ yellow to lower contrast. I've also used Kodak filtration charts, but they just show M & Y, not both together. However, I agree with the fellows above that the actual unit values (points filtration) don't really matter when it comes down to it. After awhile, you can get a feel for it. Using a step wedge is a great idea too, especially if you use more than one type of paper. You can see how different papers handle contrast across their range.
-- DK Thompson (email@example.com), March 10, 2001.
You can take a look at
http://www.kodak.com/global/en/professional/support/techPubs/g24/g24.s html#Filtration Values for Common Black-and-White and Color Enlargers
It's a tech publication for Kodak Polymax fine art paper (what I've been using recently). It gives you some filtration values to start with based on the enlarger you are using (Saunders, Chromega, etc). You can probably find similar info on other paper manufacturers' web sites.
Nowhere on the chart does it indicate using yellow and magenta together. Correct me if I'm wrong, but a yellow filter will remove blue light, and a magenta filter will remove green light. If you dial in magenta and yellow at the same time, then the only light you're passing through is red (which would be removed by cyan filtration), and multigrade paper isn't very sensitive to red. This all assumes you are dialing in equal amounts of yellow and magenta. Now if you want to split print using magenta and yellow, that's fine, but they have to be done separately.
-- Dave (firstname.lastname@example.org), March 10, 2001.
In response to Joseph A. Dickerson's response stating that you have to use both Y and M filtration, that is not true. When you use both Y and M, the result is RED! If you have, say, 30Y and 60M, the result will be 30R and 30M. For VC paper, Red is, for all practical purposes, the same as neutral density. Therefore, a 30Y and 60M setting would result in the same contrast as a 30M setting alone. This 30R "neutral" density is used to (hopefully) acheive the same exposure at all grades. With Kodak's VC papers, you can use Y or M individually with no contrast problems. The exposures at the different filter grade settings would vary.
-- Ken Burns (email@example.com), March 10, 2001.
If you're fussy, you can test and calibrate a paper/head combination for exact contrast grade points. See the "The Variable Contrast Printing Manual" by Steve Anchell. If you only use one paper, you can wing it but if you use several, calibrating seems like a reasonable but tedious step.
-- John Hennessy (firstname.lastname@example.org), March 10, 2001.
In response to some of the responses, one can use either Y or M, or Y and M. The tables that use both Y and M simultaneously are making an effort to speed-balance the "grades". As an example, Ilford gives both kinds of tables in the pdf file on their web site for Ilford Multigrade IV. Their description: "Dual filtration values usually need longer exposure times than single filtration values, but may need less adjustment to exposure times when changing contrast."
If you want to learn how to precisely speed balance your color head, or just more about variable contrast paper, the articles by Paul Butzi are excellent: http://www.butzi.net/articles/articles.htm
-- Michael Briggs (email@example.com), March 11, 2001.
Raven, a useful starting point can be found on the Ilford web site, they list filtration tables for single and dual filtration. Regards Paul
-- paul owen (firstname.lastname@example.org), March 11, 2001.