Also different colour heads/different enlargers have different values. Some enlargers use 'Kodak'values such as Dunco and LPL, others use Durst values and Leitz for the V35 had a value all to itself at one time, but now it seems they are using the Kodak figures.
Who peed in your cornflakes and why are you taking it out on me? You'd have to do as much testing to accurately, repeatably yield that quarter stop with altering developer strength, which would never be as consistent as changing the filtration, because as developers get used and as they age, the impact of altering dilution changes. And as far as changing filtration is concerned, if grade 3 is 50M, grade 3.5 is 75M and grade 4 is 120M, then you can derive a reasonable working approximation of grade 3 1/4 from the logarithmic scale. It ain't rocket science, it's simple math. But in the long run, what does it matter that it's precisely grade 3 1/4? If you need more contrast than grade 3, and less than 3.5, dial in 60M (using my above hypothetical example), and if you don't like that, tweak it up or down a few CCs. Unlike color printing, a tweak in filtration finer than a quarter grade isn't going to yield a discernable difference anyway. Maybe your densitometer can tell the difference, but it's highly unlikely that your eye will.
Originally Posted by litody
The definitive test for your situation is to calibrate your process with a projected step wedge. I use it to figure how old paper responds.
Print 170 (or your max) M then 30 less to 140 then once you are down to 110M, start going down in 15M steps to zero, then start winding in 15M Y untilo 110, then wind in 30 steps to 170Y. Prints do not need to be large. Mine with a 6x6 step wedge end up a bit more than 2.5" square, projected with a lot of bellows extension. write filtration in back with pencil. Process all at once for say 2'. Read the number of steps from all black to all white, and figure out what fitration gave what responses, Build a table. The next step is to add back in neutral density to give constant expsoure times with some selected image tone.
I learned all of this from a post written on this site by the usuer 'noseoil' about 5-7 years ago.
I ignore all the alleged grade values and complicated nonsense associated with it. With my enlargers
plain white light prints most VC papers at a decent mid-range, about like Grade 3. If you want more
contrast, dial in some M, if you want less, use Y. Some papers will not obtain a good DMax unless
you expose both emulsion layers a little. Then you can learn how to split-print using different filter
values selectively. I just run simple test strips, and tweak the colorhead if necessary by simple
visual evaluation after I dry down the strip.
OP, Paul Butzi has a detailed and quite complex article on the subject, the link to which I found many years ago on APUG but I can't recall the URL. If you want to get into the subject, do a google or maybe search APUG.
Just be prepared to read it several times to get an understanding.
Did some digging and found this thread. I want to use a Beseler Dichro head (23cIII) for Ilford and Kodak VC paper.
I found this on Ilford's site. From what I can see, I can choose "single" (Y or M) or "dual" (Y and M) filtration. Both will accomplish the necessary contrast change, but "dual" will have the benefit of making exposure settings closer to constant when changing contrast setting.
Do I understand this correctly?
Any suggestions for Kodak paper? If not, I'll just try the Ilford settings and see where that takes me.
There used to be charts available online with filter settings for both Kodak and Ilford papers. Frankly, if memory serves, they really weren't too far different until you got into the extreme ends of the filtration spectrum (trying to hit grade 00 or 5+), so I'd start with the Ilford recommendations and if you don't like what you get, tweak. That's one of the great benefits of using a dichro head - you can set in-between grades and aren't locked in to only Grade 3 or 4- if you need 3 1/4, you can get it by adding just a few more CCs of magenta over the Grade 3 recommendation.
no, but keep in mind that here is an ISO standard for paper grades but no standard for filter numbers.an ISO grade 3 and a number 3 filter have little in common. it is best to calibrate your color enlarger to the standard ISO grades ala Paul Butzi's method or mine.You'll find the former on the web and get the latter fupon emailrequest to firstname.lastname@example.org
Originally Posted by RedSun