All well and good, but red safelight will produce a cyan fog on RA-4 materials. I'm perfectly okay with dim for color, but I'd really rather not work in total darkness if I can get even "not bang my head on the enlarger head" levels of safelight for that task. And the amber is much more comfortable for B&W printing as well. I do have an old red bulb safelight, so I can still use that for ortho materials like Harman Direct Positive.
I didn't know you could have any sort of light with RA-4
It's a source of some controversy, but there's a very deep valley in the spectral sensivity curves of the three layers of RA-4 paper, where the red and green curves cross around 585 or so nanometers. The way I read the chart for Fuji Crystal Archive, that specific wavelength is five to seven stops less sensitive than the peak of the green curve. That means you can put a dim light right in that valley and it will take long enough to produce noticeable fogging to let you work in "man, it's dim in here" rather than total darkness. And that's a HUGE difference.
Beware, though, with the (otherwise excellent) Foma papers --the multigrade ones--.that seller (SuperBrightLEDs) also has an amber bulb that has its peak at 590nm -- it's been confirmed by other users here to be safe on most VC and graded papers
Beware, though, with the (otherwise excellent) Foma papers --the multigrade ones--.
It has more to do with the relatively good availability of red LEDs that work with photographic paper vs. amber LEDs that work with photographic paper.It amazes me about the persistence of use of RED in the darkroom when even Kodak buiilt safelights that were furnishd with AMBER filters since the 1960's.
That was in the days of mostly graded papers. Variable contrast paper has a broader spectral sensitivity (Ilford is 350-550 nanometers). Orange light is in the 590-625 NM range, and red light is in the 625-700 nm range. Red LEDs are about 630 nm, monochromatic. Sodium lights, also monochromatic, are 589 nm. The roll-off of the paper sensitivity above 550 nm is somewhat gradual, so the higher above 550 nm, the less change of fogging over extended periods of time. Red is safer than orange. Also, red LEDs are widely available. I don't see any advantage to using orange lights. Just turn-up the brightness of the redIt amazes me about the persistence of use of RED in the darkroom when even Kodak buiilt safelights that were furnishd with AMBER filters since the 1960's.
I used Jobo safefights, purchased in the early 1990s, which used LEDs in 3-position lens safelights which were designed for use with B&W paper, color neg print paper, and color transparency print paper. As I no longer had space to set up a darkroom, I recent sold off a considerable portion of equipment, including two Jobo MaxiLux 6240 LED safelights.
That was in the days of mostly graded papers. Variable contrast paper has a broader spectral sensitivity (Ilford is 350-550 nanometers).
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A lot of us can't just place an order to a US supplier and get something shipped quickly and cheaply.
That was my perception as well, Tom. It is always a problem whenever a U.K. or maybe a European is looking for information on LEDs and stuff that we cannot get here or we cannot be sure that U.S. LED X is the same as U.K. LED YI suspect some of our US contributors don't appreciate how much choice, availability, and convenience they have compared to the UK or Canada.
A lot of us can't just place an order to a US supplier and get something shipped quickly and cheaply.
Tom for clarification: Are these the same 16 leds you had in the transparent box hung by strings from the ceiling and with the Ilford filter over them how does the light compare to the former 25W incandescent?
Red works with all contemporary b&w papers, amber works with most, but not all. Try printing on fomabrom with an amber safelight...amazes me about the persistence of use of RED in the darkroom when even Kodak buiilt safelights that were furnishd with AMBER filters since the 1960's.
Red works with all contemporary b&w papers, amber works with most, but not all. Try printing on fomabrom with an amber safelight...
Btw, I also have one of those Jobo three-colored safelights. It's about as effective as trying to light a soccer game in a stadium with a flashlight.
I know red is for Orthochromatic materials, but I don't know offhand anything modern that fits that description apart from lithographic films.
Ha ha! I only used mine for color work, so dimness was inherent to color printing, and I never noticed the brightness of B&W.
As for Fomabrom, this from their tech data sheet
"FOMABROM is routinely processed at indirect safety illumination with wavelength of 575 nm and higher, corresponding colour of safety illumination is yellow, yellow-green, amber or orange colours are recommended."...no mention of Red!
I know red is for Orthochromatic materials, but I don't know offhand anything modern that fits that description apart from lithographic films.
You quoted the specs of the fixed contrast Fomabrom. Fomabrom Variant requires 625nm or higher.
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