Anyone capable of using the blue filter on Peak enlarger focusers?

[jose angel]

My Peak enlarger focuser has given me satisfying results for years. I recently found its never-used blue filter inside a box during a darkroom removal. I`ve just tried to use it again... oh, my... what a hard task!

I know I have never had a good eyesight, maybe I`m doing it wrong, or lenses should be even more faster. My enlarger use a strong light source (LPL 7452), and the lenses are fast&sharp ones... (150/4 and 105/4 Apo-Rodagon).

I`d like to use it, but definitely I can`t. Does anybody in the world (Ctein aside), is capable of distinguishing the grain with the filter attached???

[ic-racer]

I`d like to use it,

I use mine as a lens cap.

[Steve Smith]

Gene Nocon recommends the blue filter in his book Darkroom Printing.


Steve.

[LaurentB]

I`d like to use it, but definitely I can`t. Does anybody in the world (Ctein aside), is capable of distinguishing the grain with the filter attached???

I just read "Post exposure" last week, and he does not recommend using the blue filter (see p77) due to chromatic aberration in the eye.

[Lachlan 717]

Clyde Butcher uses blue light.

[Drew Wiley]

I have bright enough light sources, even my coldlight, where viewing thru the blue filter is
easy enough. But since all my enlrgr lenses are well corrected or even downright APO,
why bother? There's no focus shift per white versus blue light. Maybe that was the case
long ago, but it sure ain't a problem with any enlarging lens I personally own.

[jose angel]

Laurent, I have to re-read Ctein`s pages, I have forgotten it. Thanks.

Drew, incredible. It makes me think my eyesight is going worst. I barely can see the image, so the grain on FP4, no way.

I have been printing this afternoon, no problem with sharpness, as usual. But maybe I`ll perform a test, anyway. One day...

[Leigh]

... he does not recommend using the blue filter (see p77) due to chromatic aberration in the eye.
He (ctein) is well-known for experiencing aberrations that are beyond the ability of mere mortals to identify.

- Leigh

[Drew Wiley]

The average eye is in fact a little less sensitive in the blue. And there was a day when your choice of printing paper was entirely graded blue-sensitive, and certain graphics films
ortho, but mainly blue-sensitive, and some enlarging lenses perhaps not ideally corrected.
A blue filter might also help focus on grain if you've got a yellowish pyro stain on the neg.
But what it gives in that respect it takes away via substantial density.

[Drew Wiley]

Jose - my colorheads as well as coldlights are pretty souped up. I don't think the problem
is your own eyesight.

[ROL]

I barely can see the image, so the grain on FP4, no way.

I feel your pain. I have never been able to use the Peak's blue filter. Likewise, I find it exceedingly difficult to focus grain on most of my PMK Pyro developed 5x7 FP4+ negatives, at anything greater than an 11x14 enlargement. My coldlight won't put out enough blue to grain focus, and in fact the "focus" light switch engages both the green and blue at full intensity. 120 Rodinal developed negatives are quite accommodating, though.

[joselsgil]

I find it hard to focus with my Peak II grain focuser, if the enlarging lens is wide open. I usually stop it down in order to see the grain a little better. Then again, my good eye ( left eye) is developing a cataract and is difficult to focus compared to a few years ago. I have been developing my film in PMK for about a year now, so they do have the Pyro stain.

Jose

[Doremus Scudder]

As Drew points out, using the blue filter is no longer necessary as long as you have a modern enlarging lens. Older lenses used to focus blue at a different plane than red and green; and the graded papers used at the time were sensitive to the blue. If you mis-focused the blue, you mis-focused the print. Hence the blue filter.

Nowadays, enlarging lenses focus blue at the same plane as red and green (or at least close enough) so that you don't have to isolate the blue and focus it. Plus, VC papers are sensitive way into the green region.

I've never used the blue filter on my Peak grain magnifiers, and am more than happy with my focusing.

Best,

Doremus

[ic-racer]

As Drew points out, using the blue filter is no longer necessary as long as you have a modern enlarging lens. Older lenses used to focus blue at a different plane than red and green; and the graded papers used at the time were sensitive to the blue. If you mis-focused the blue, you mis-focused the print. Hence the blue filter.

Nowadays, enlarging lenses focus blue at the same plane as red and green (or at least close enough) so that you don't have to isolate the blue and focus it. Plus, VC papers are sensitive way into the green region.

I've never used the blue filter on my Peak grain magnifiers, and am more than happy with my focusing.

Best,

Doremus


Koana's paper was published in 1950. The Peak 1, designed and marketed after that. Enlarging lenses on the market at that timer were mostly color corrected. For example the 1950 Wollensak 4-element Raptar was marketed as color corrected and even the lowly 4-element Schneider Comparon was color corrected.

[jose angel]

I know my prints are sharp, so no issues at all with focusing. I see focus difficulties with this item are normal, so I feel a bit better... :)

I think I`ll take the camera to shoot an USAF chart tomorrow, just to have it on a negative for testing... once I have it I`ll post my results here. No surprises expected, anyway.

Thank you all very much.