....In some Forums I read that it should ne 589nm. I dont know If the 9nm makes much diffrence. I also work with exposure Times of 4-5 Seconds on my enlarger so that the paper is not in the darkroom light for to Long.
Btw I use the Ra4 Paper from Fotoimpex.
I bought a ra4 safelight on eBay.
the makers of the DUKA presumably tested their light with RA4 paper
But when I use the Filter ony my enlarger to get Rid of the Blue, I get the right colors for my picture.
Today's color paper is not suited for use with a safelight. The safelight levels it'll tolerate are so low that they're barely useful. At best you can turn on a very dim safelight for a few seconds, but even that is risky. Just work in the dark instead; it's not so bad once you get used to it.
Color safelights stem from the old days (prior to about 2003) when paper was much slower than today.
Not with today's digital papers. The DUKA lights originate far prior to those. Many people seem not to realize that the paper has changed, but their 1980s safelights are still the same.
That's correct. The number of manufacturers is now down to two and both only produce papers for digital exposure. This means they're fast papers, and they do not have the requirement of safelight handling.there are now no safe papers to be purchased now from any maker of paper but on the other hand today's colour papers can be used for a few seconds at a very dim illumination
I have placed a few small bits of phosphorescent tape at some strategic places of my darkroom.
That's correct. The number of manufacturers is now down to two and both only produce papers for digital exposure. This means they're fast papers, and they do not have the requirement of safelight handling.
I'd encourage you to do your own testing. I cannot answer for you what works in your hands, in your darkroom and for your standards of what makes an acceptable print.
It starts to shifts to cyan long before you see fogging on the white borders. Maybe you never noticed this; I can only account for my own testing.
but not caused by several seconds of a blast of Y+M?
what it was about the 589 nm wavelength that starts the shift to cyan
Yes at times a slight shift to cyan can be difficult to see
Thanks I think what I am asking is : What is it about the speed of the digital paper v the previously slower paper that makes the cyan layer in digital paper compared to the previous cyan layer sensitive to the wavelength at any safelight exposure or is it simply more sensitive than before, such that the shift to cyan begins at a much lower exposure level of the safelight?Only the cyan layer is sensitive to that wavelength. The sensitivity plots in the datasheet give some hints, and again, it's easy enough to test.
In which case we are back my earlier question of whether there is any indication as to what the level of exposure is in terms of seconds/mins. It sounds as if there is no source of information on this such as Fuji or Kodak and it is as you suggest "trial and error" to find what that level is
Every darkroom is different. There's no published number of lux-seconds and it wouldn't make any sense to have such a number because it would be impossible to accurately measure it for the vast majority of users. Moreover, the manufacturer (Fuji) doesn't bother investigating this because darkroom printers represent a vanishingly small percentage of the total paper consumption.
So the solution here is to do your own testing instead of trying to inquisition an answer from someone that ultimately proves to be of little use to your own situation.
I've tested it up to 12 seconds within a few inches of Fuji RA4 paper without fogging it.
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