Why and When to Use Colored Filters While Enlarging B/W Prints

[danac]

I have a set of these but have no clue as to what to do with them. Any helpful comments would be appreciated.

[Alan Marcus]

Historically, the darkroom with the enlarger had shelfs and drawers filled with boxes of unexposed photo paper. We are talking, glossy, silk, pebbled, simi-gloss, singe weight, double weight and lots more. In addition, most of these textures were labeled based on its contrast. Grade 2 was “normal”, we are taking grade 0t through grade 6. What I am trying to tell you is, our paper inventory excessive.

 

Variable contrast photo paper saved the day, One box or this magic stuff and contrast changing filters cut our inventory to a manageable level. These papers have two emulsion coats. One is sensitive to blue light and the other to green. One coat is high contrast and the other low contrast. With a little practice, we learned to pre-judge the negative and the resulting print it will make. We learned what contrast grade of paper was the best fit to produce an “optimum” print.

 

The filters adjust the white light of the enlarger, changing the ratio of blue to green exposing light. This cleaver method allows a single box of paper to operate at every possible corrective contrast level.

 

The yellow filter is a blue blocker, the magenta filter is a green blocker. These are in different strengths allowing the one box of paper to operate at every possible contrast level.

[JDMvW]

Variable contrast photo paper saved the day, One box or this magic stuff and contrast changing filters cut our inventory to a manageable level.

Exactly.

[rodeo_joe1]

This should tell you all you need to know.

 

The purplish filters give you harder contrast, and the yellowish filters softer contrast.

 

If you have a set of Cyan, Yellow and Magenta filters, they're for colour printing and have limited use for multigrade printing only after tedious calibration.

 

If the filters are old (>5yrs) they'll most likely be faded and not have the marked value of density.

[glen_h]

Polycontrast was explained to me by my grandfather when I was about 10.

 

Not so much later, I inherited his darkroom equipment, including some Polycontrast

and a Varigam filter set. (Which is supposed to work fine with other papers.)

 

And yes the explanation was blue sensitive and green (and blue) sensitive layers

with different contrast. More recently, though, I learn that the two have the same contrast.

The math is more complicated than I can explain here, but if you shift and add two

H-D curves, it almost makes sense. In the low contrast case, one curve follow the other,

resulting in a long curve with low slope. When they are one on top of the other, and add,

the result is shorter with a higher slope.

 

But mostly you don't need to know that, except that different filters,

with numbers on them, give you different contrast. 2 for normal contrast,

3 for higher (low contrast negatives), and 1 for lower contrast (high contrast negatives).

[danac]

Thanks all. Time to experiment.

[tommyfilmist]

Thanks all. Time to experiment.

Its not really a time to experiment..

 

Its time to see how old they are.. not all filters last... ie more you use them the more they fade out.

 

Dichroic color heads on the other hand dont fade. Thats why i splurged on got a used dichro head..

 

figure out who made the filters and try to get ahold of them. Best rule of thumb is that if the company no longer exists, the filters are most likely NOT going to be good for use.

 

Ilford sells a decently good set, not cheap, but not expensive, but its going to work 100% with the instructions for ilford paper

[jose_angel]

Hmmm, Tommy, I'm not sure about it.

IMHE, all filters fade, but not that fast.

I still use some decades old Ilford MG filters; compared to the recent ones, of course *some* look to be faded, but not that much. Or maybe, they made them at a different value, which I also believe. Manufacturer`s charts never worked for me at all.

Dichroic enlargers, as far as I know, use filters too. I tend to think that powerful light sources and heat (like the ones used on most dichroic enlargers) are worst in terms of plastics durability. I now use LED sources, which I assume are way more "filter friendly", so I'm feel confident with box filtering.

[tommyfilmist]

Hmmm, Tommy, I'm not sure about it.

IMHE, all filters fade, but not that fast.

I still use some decades old Ilford MG filters; compared to the recent ones, of course *some* look to be faded, but not that much. Or maybe, they made them at a different value, which I also believe. Manufacturer`s charts never worked for me at all.

Dichroic enlargers, as far as I know, use filters too. I tend to think that powerful light sources and heat (like the ones used on most dichroic enlargers) are worst in terms of plastics durability. I now use LED sources, which I assume are way more "filter friendly", so I'm feel confident with box filtering.

as it has been put out on photrio, the filters in a dichroic colourhead do not fade.. something about the TYPE of material, adn the way they work in relation to the light flow.

 

on photrio they say that the filters like ilford sell are only good for 5 years of usage, and by usage they mean "i make prints every week or day". Some claimed to have worked in college darkrooms and had the filters go useless in under two years

[jim_gardner4]

As long as you’re not wanting to print grade 5, does it matter if they do fade? I always use enlargers with colour heads and have never dialled in x amount of magenta or yellow to produce a grade 0,1,2,,,, print. I start about 0 or maybe 20 magenta (depending on negative) then make a decision to alter contrast based on test print. I often find +\- 10 on the dial makes a fair bit of difference to the print but I have no idea what contrast grade the final print is.

[glen_h]

Yes, grade 5 is always the hardest to get.

 

Some people might be very specific with the exact contrast they want, but I don't think I am that good.

 

In any case, adjust until it comes out like you want. I would be surprised if they faded a lot, unless you

leave them in the sun.

 

I have the Varigam filters I inherited from my grandfather some years ago, and some sets

of acetate about 3in square filters. Also, an actual set of Polycontrast filters, though I haven't

used those. That latter and the Varigam are thicker plastic in molded plastic frames.

[AJG]

I used a set of Ilfiord Multigrade filters for 20 years or so (thousands of prints...) and never noticed any changes in contrast while printing. These went under the lens since I was using it with a cold light head. When I wasn't using them they lived in their box so they had minimal light exposure outside of printing.