Filtration

redbandit · Nov 30, 2022

Has the filtration standards for Ilford and "kodak" filters changed over the years?

Im just curious as I am using a beseler dichro head for color prints, and the original paper work has a nice section of contrast settings for ilford and kodak paper. And the original paperwork doesnt jive with what Ilford includes in its current production paper.

IE original paperwork says for example 10y + 30M for "2.5 contrast" the new ilford can be 21y + 35M

is it just a change in the paper that is tossing me off?

MattKing · Nov 30, 2022

The paper has changed.

redbandit · Nov 30, 2022

then

MattKing said:
The paper has changed.

how does one know what each brand of paper actually needs then

MattKing · Nov 30, 2022

Go to the paper manufacturer's data source.
And understand that one manufacturer's grade 2 will likely be at least slightly different than another's.
And that grade 2 may differ subjectively between papers, and paper surfaces.
The grade tables are actually a remnant from the days when fixed grade papers were the norm, and manufacturers were trying to help you mimic the fixed grade papers with variable contrast paper and equipment.
Now variable contrast is the norm, so most people arrive at their own preferences by adjusting the tables to their needs.

snusmumriken · Nov 30, 2022

We had a thread about the filters a couple of months back. I asked Ilford directly whether they had changed, and yes there was a single change in I think 1992 (do a search on the forum to check).

Paul Howell · Nov 30, 2022

Kodak changed at least one time, as I recall their first version of polycontrast was similar to Dupont, then sometime in the 60s (?) changed both the paper and the filters. Old sets of Kodak filters show up on Ebay once in a while.

xkaes · Nov 30, 2022

No matter what filters or papers you use (I use Ilford on my MXII, and Varigon on my CB7), it's important to make some tests. I used Stouffer's step wedges, and found that the suggested changes in exposure time (ex.0-3 are the same, and 4-5 are double, etc.) are often inaccurate. I created my own table for changing the exposure times when changing from one filter to another.

And when you are determining how much change there needs to be to the exposure time, you'll figure out how much change in contrast there actually is.

redbandit · Nov 30, 2022

Its hard to get inkpress multi tone data. Cant even get the manufacturer to admit they make it via their amazon store.

koraks · Dec 1, 2022

redbandit said:
Its hard to get inkpress multi tone data

How's this related to your initial question...? Just curious; I've been looking for printing process benchmark data like channel densities for a bit, so it piqued my interest.

Anyway, don't worry too much about grades. They're as you have noticed by now rather fleeting and even somewhat random choices that can vary over time and between manufacturers.
If you need more contrast, dial out yellow or dial in more magenta. If you need less, do the opposite. With blue & green filters: more blue is more contrast, more green is less contrast. It's all you need in practice!
Nobody really cares what grade a print was made on. It'll be liberating to let go of the construct of grade. The only reason grades can be helpful is to remake the same print based on your own notes. If you want that, just jotting down filter settings will accomplish the same anyway.

redbandit · Dec 1, 2022

koraks said:
How's this related to your initial question...? Just curious; I've been looking for printing process benchmark data like channel densities for a bit, so it piqued my interest.

Anyway, don't worry too much about grades. They're as you have noticed by now rather fleeting and even somewhat random choices that can vary over time and between manufacturers.
If you need more contrast, dial out yellow or dial in more magenta. If you need less, do the opposite. With blue & green filters: more blue is more contrast, more green is less contrast. It's all you need in practice!
Nobody really cares what grade a print was made on. It'll be liberating to let go of the construct of grade. The only reason grades can be helpful is to remake the same print based on your own notes. If you want that, just jotting down filter settings will accomplish the same anyway.

i understand what you be saying, but you need to understand something important.

I am still at the setting out stage with my enlarger. Every little bit of process i had made earlier this year is gone. In fact i think the only retention i have had is safelight safety standards and keeping my paper locked up tight. Everything else is just gone.

If a person has done 2,000 prints on their machine, they can get the rough idea of "oh i dont like how the projected image looks on the easel, ill turn the yellow dial +10"

Im still at the stage where I am trying to learn
"ok so i did the dials at 0 0 0 for a grade 2 contrast setting, and the image isnt crisp enough. That means i need to do the dual filtration method and use Y and M filters at teh same time"

koraks · Dec 1, 2022

So try dialing in any amount of filtration, observe the result, and adjust upward or downward as desired. Again, grades don't really matter. It even doesn't really matter where grade 2 might be. If you dial in +10 yellow to get contrast down and you don't see much of an effect, fo another strip with +40 and see what you get. Soon enough you develop that feeling for how much you might need. It takes far less than 2000 prints, fortunately!

Bill Burk · Dec 1, 2022

I think it’s fair to say dial up M for more contrast and dial up Y for less. Practically every multi grade paper has green sensitive low contrast layers and blue sensitive high contrast layers. Think of yellow as “minus blue”, and magenta as “minus green”. Equal parts is usually grade 2 so that’s why all zero should be good for a normal negative.

The color head combinations are chosen first to give the right contrast, but also to give consistent exposure and third they include red light so you can focus. The only thing that matters to the print is getting the right mix of blue and green so you get the right contrast.

You should be fine starting out with the published filtration combinations from Ilford.

RalphLambrecht · Dec 1, 2022

redbandit said:
Has the filtration standards for Ilford and "kodak" filters changed over the years?

Im just curious as I am using a beseler dichro head for color prints, and the original paper work has a nice section of contrast settings for ilford and kodak paper. And the original paperwork doesnt jive with what Ilford includes in its current production paper.

IE original paperwork says for example 10y + 30M for "2.5 contrast" the new ilford can be 21y + 35M

is it just a change in the paper that is tossing me off?

All these filtration values must be seen as rough estimates. They are only good at starting values. The rest is calibration and fine-tuning.

GregY · Dec 1, 2022

RalphLambrecht said:
All these filtration values must be seen as rough estimates. They are only good at starting values. The rest is calibration and fine-tuning.

Well said Ralph.... that's where the decisions start.... while printing

redbandit · Dec 6, 2022

If a contrast grade 2 comes out solid black, of a seagull on a parking lot, is it safe to assume that increasing contrast wont help much?

pentaxuser · Dec 7, 2022

redbandit said:
If a contrast grade 2 comes out solid black, of a seagull on a parking lot, is it safe to assume that increasing contrast wont help much?

If the print has turned out solid black at grade 2 then I fear that decreasing the contrast might not help either

If the above is not rhetorical so requires no answer then some qualification of what you mean might help

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