What I learned today

[coops]

Several weeks ago I purchased a used Super Chromega D Dichroic II. I have not used it because, well I don't know how. No instruction manual and all the guy I bought it off could tell me was " focus with the white light, stop down two, and then use the high setting for the light. And avaoid the yellow and cyan". Well, it's a start. So I opened a pack of Ilford multigrade RC paper and made a test strip. Around 22 seconds at F8 looked best for the blacks, but the whites were kinda grey, and dull.
I decided to experiment and up the magenta from 0 to 35 and do a little dodging. Better, so I went up to 45 on the magenta, better, then to 65, great. 70 was not so good. Then I develiped the paper an extra minute from 2 to 3 mins, and now my whites are pretty much white.
My prints now, in my opinion, look better than my inkjet prints, and I thought they were pretty good. But this was far more satisfying. It seems the variables are endless for printing. Where do you stop with the experimenting?
Can someone tell me what the magenta was doing to the print? Was it increasing contrast?
And do the cyan and yellow do anything for black and white?
Cheers

[Vaughn]

Basically, the magenta (red) filter was acting in the same manner as variable contrast filters. There are charts somewhere that equate the amount of filtration to the filters. if you need to lower contrast, use the yellow only.

The magenta filter will block light -- the more filtration used, the more light it blocks. So you may find that once you have your contrast dialed in (via the magenta dial), you may need to fine-tune the actual exposure. Some of the charts mentioned above will give you a combination or yellow and magenta filtration -- they are designed to give you a consistant exposure.

Cyan will only act like a neutral density filter -- not change the contrast but increase the amount of exposure needed.

Vaughn

PS...one stops experimenting when one goes too far...then one backs up to what one wants to see.

[Vlad Soare]

Variable contrast paper is made of two layers. One of them is very, very high contrast and is only sensitive to blue light. The other one is very, very soft and is only sensitive to green light. By controlling the amount of green and blue in the projected light, you control how much weight to give to one layer or the other. In other words, you control the contrast.
Subtractive filters absorb light of the complementary color. The complementary colors of magenta and yellow are green and blue. Magenta filters absorb green light, yellow filters absorb blue light. The more magenta you use, the less green light hits the paper and the less the soft layer is affected by the exposure. The same goes for the yellow filter and the blue sensitive layer. Cranking up both magenta and yellow to the maximum will give you almost no image at all.

So, you start with no filter at all. If the image is too soft, you dial in a little magenta and try again. If it's too hard, you dial in a little yellow and try again. Repeat until you get the contrast you want. The exposure duration will change, so you'll have to make new test strips every time.

The cyan filter is useless for B/W printing, unless you want to add some neutral density. Multigrade filters (the ones you use separately, in a drawer) are not just magenta or yellow, they also have a certain amount of neutral density, to ensure that the exposure remains unchanged when you switch from one grade to another. You can emulate this with a dichroic head by using all three colors. The procedure is explained here.

[dsphotog]

Ilford paper packages include an instruction sheet containing 2 charts of contrast control filter values for color head enlargers,
single filter(chart 4) or, my preference, the dual filtration combination of yellow & magenta filters(chart 5). This is a simplified version of the chart in the link shown in the above post by Vlad. It works very well. if you test for exposure at perhaps grade 3 -(23y/56m) then want a different contrast, say grade 4, (6y/102m),the exposure stays consistant!
I've made test prints of grade 00 through 4 1/2 using this method,
the exposure is the same, try it it really works!!
the exception is grade 5, just dial in 199 magenta / 0 yellow, but it will need more exposure.
Happy printing!!
David Silva
Modesto Ca

[Clay Turtle]

Several weeks ago I purchased a used Super Chromega D Dichroic II. I have not used it because, well I don't know how. No instruction manual and all the guy I bought it off could tell me was " focus with the white light, stop down two, and then use the high setting for the light. And avaoid the yellow and cyan". Well, it's a start. So I opened a pack of Ilford multigrade RC paper and made a test strip. Around 22 seconds at F8 looked best for the blacks, but the whites were kinda grey, and dull.
I decided to experiment and up the magenta from 0 to 35 and do a little dodging. Better, so I went up to 45 on the magenta, better, then to 65, great. 70 was not so good. Then I develiped the paper an extra minute from 2 to 3 mins, and now my whites are pretty much white.
My prints now, in my opinion, look better than my inkjet prints, and I thought they were pretty good. But this was far more satisfying. It seems the variables are endless for printing. Where do you stop with the experimenting?
Can someone tell me what the magenta was doing to the print? Was it increasing contrast?
And do the cyan and yellow do anything for black and white?
Cheers

Hmm . . those answers are good advice but . . I wonder if they should be giving you a fuller explanation? How much experience do you have with shooting & printing?
I ask this because I started a thread dealing with my question about an alternate processing of b&W. I was pointed to a book that dealt with alternate methods but wanted to browse the work to see how relevant it would be in regarding what I was doing. So I went to the library, they didn't have the book. In fact they had little on photographic printing and what they did have was more about digital . . . but I did pick up one old book to browse being I was there.
Interesting I too found some useful information in the volume, the authors opening dialog dealt with a general aspect of shooting b&w. How does one tell from a negative if they are getting the correct exposure? So there is an aspect of that multi-contrast paper comes into play. What are you seeking to do?
Generally, one finds mostly rc (resin coated) multi-grade (contrast) b&w paper which is great stuff but his suggestion in finding out what you (the reader) should do to find out if they are producing a normal negative is to print it normally. The process he advised was to set up the enlarger at the height (with negative) in holder then remove the negative and do a test strip at the (nornal) strait setting. Process the paper then establish at what length of time (duration) produces the dark black exposure. As you are exposing strait light this represents a black in the print for that particular setting (f-stop, height) & that particular paper (grade). Thus establishing your normal exposure which then is related to what you need to do to get what you want in the print. Be aware that development time in the paper tray just as development time with film changes the output.
PS: One of my pet projects in printing is to have the white of the border of the print be the same white as the high white values in the print. Which forms or sets the standard for the full range of grey in the print. Just one of my idiosyncrasies.

[Brian Ellis]

Variable contrast paper is made of two layers. One of them is very, very high contrast and is only sensitive to blue light. The other one is very, very soft and is only sensitive to green light. By controlling the amount of green and blue in the projected light, you control how much weight to give to one layer or the other. In other words, you control the contrast. . . .

Just as a matter of interest, there actually aren't two separate layers, one of which is sensitive only to blue and the other only to green. Both "layers" are sensitive to some blue and some green. It's just that the "high contrast layer" is more sensitive to blue and less to green and vice versa for the "green layer." I put "layer" in quotes because there really aren't two layers either. And finally, some papers (e.g. some Ilford papers) actually have three "layers." There's a good explanation of how VC papers work in an article by Phil Davis that appears in the October, 1994 issue (I think) of Photo Techniques magazine.

[coops]

Thanks for the responses. Is there an advantage for me to choose a low grade paper, like a #2, and play around with it and not use the magenta / yellow on the printhead? Are there less vauiables this way? Keep in mind all this is very new to me?
Thanks again

[Bobf]

If you use a graded paper (grade 2 or grade 3 or whatever) the filtration will not do anything. Only variable contrast (VC) papers respond to the filtration, not fixed-grade papers. Important to distinguish between the two.

There are ways to alter the contrast of fixed grade papers including using different or two-bath developers, flashing, water-baths etc but changes are limited to about one grade change and require experience to use effectively.

Stick to VC papers for starters unless you are willing to take the time to control negative contrast and learn the techniques involved in using fixed-grade papers. I confess, I rarely print on fixed-grade myself: only occasionally using Kentona. Some others use them exclusively (but they are pretty much always better printers than me to start off with!)...

This Ilford PDF (http://www.ilfordphoto.com/download....0201152306.pdf) explains contrast control with VC papers (the same rules apply to other manufacturer's papers: only the filter values are likely to change). There are other useful documents on www.ilfordphoto.com but they are scattered about a bit, rather than all in one location.

Have fun, Bob.

[Clay Turtle]

Thanks for the responses. Is there an advantage for me to choose a low grade paper, like a #2, and play around with it and not use the magenta / yellow on the print head? Are there less variables this way? Keep in mind all this is very new to me? Thanks again

Don't know if your question is in response to my comments or not but as Bobf states it is not necessary to use graded paper . . . an RC is shorter (quicker) & therefore perhaps easier to use.Most papers (?) will print normal using only the condenser but as you are using a diffusion enlarger (color head) I am not so sure about it . . . the Beseller 67 in the darkroom has a lever that is used to switch the setting for b&w print? (but I am assuming these aspects, not experiences)
No, doing a primary print @ normal grade (contrast) is like setting up your LF camera. I set up by setting all the controls (shift, swing,tilt, etc) to a parallel & perpendicular as a reference point then make adjustments according to the scene. Starting @ normal contrast & having established an general duration of exposure gives you a reference point when you print then you can make adjustments of contrast. For now anyway, you need to develop a feel for where the negative is at, once you become familiar with the light intensity of the look of a normal print, you will be able to adjust to that light level getting close to the finish settings just by looking at the level of light from the negative.

[Vlad Soare]

Brian, you're of course right. I oversimplified it to give the original poster an idea about how VC paper works and why, in just a few lines of text, with just as many details as necessary. The same would apply, for instance, with color film: if someone wanted to know how it works, I'd say it has three layers, one sensitive to blue, one to green and one to red. This would give him a better idea than if I went into details about how all layers are sensitive to blue, how separate filter layers are used, why negatives have an orange mask and slides don't, and so on.
I think my simplified version, albeit not extremely accurate, will help the OP understand how yellow and magenta filters affect VC paper, why one of them increases contrast while the other one decreases it, and why the cyan filter is of no use with B/W paper. If I'm not mistaken, this is what he wanted to know in the first place, and going too deep into details wouldn't have helped.
But you're right, I admit that my version wasn't 100% accurate.

Is there an advantage for me to choose a low grade paper, like a #2, and play around with it and not use the magenta / yellow on the printhead? Are there less vauiables this way?

Graded paper (#2, #3, etc.) has a fixed contrast. It's not affected by filtration. There are ways of altering its contrast, but for the time being it helps if you see it as a fixed contrast paper. A low grade paper will always render a low contrast image.
Variable contrast paper, on the other hand, is what I described above: it can be made to be either soft or hard by means of magenta or yellow filtering. With no filter at all it usually behaves like a medium to low grade paper.
Though it can be argued that graded paper has some advantages, I recommend you start with variable contrast. You won't look back.