Red Led's For Safelight

Ian-Barber

Admin
Staff member
Registered User
I was finding that the safe light in the darkroom was just a little on the dim side. I saw a comment about using some Red LED's.

I decided to try some multi-coloured ones operated by a remote control which allows you to change the brightness levels.

After doing some safe light testing I was impressed to see that for my tiny darkroom, the lowest setting was sufficient not to cause any fogging at all on all the papers I own.

darkroom.jpg
 

Robert

New Member
Registered User
I had a string of red LED lights in my makeshift garage darkroom until last year. I thought they were the best thing since sliced bread, super bright and paper safe. That's until I read how to do the safelight test properly and discovered that they weren't safe at all! I made the mistake of doing the coin-on-the-paper test without first exposing the paper to mid-grey. On the non-sensitised paper there was no effect from the red LEDs but afterwards the difference was remarkable. I now have a dedicated darkroom in a new outbuilding at home. I am using a Kaiser safelight at the "wet end" and an AP safelight at the "dry end" (both fitted with the standard 15W bulb). The bulb in the AP safelight makes the fitting quite hot when it has been on for a while and I'm thinking about finding LED equivalents and doing the safelight test again with them just to make sure they are OK. Kodak published a very detailed paper on safelight testing. I will post a link to it if I can find it.
 

Ian Grant

Well-Known Member
Registered User
Fogging isn't the only issue, if a red safe-light is too bright there can be contrast issues with Multigrade papers, this is due to the Herschel effect where exposure to red light destroys some of the latent image. In practice this is only likely to happen in a small darkroom and brightness, time exposed (to the red light, and distance from the paper. The consequences are to limit the range of grades making it impossible to achieve a Gd 5 and even a good Gd 4.

Some VC paper data-sheets don't recommend a red safe-light instead they recommend a OC or 902 and equivalents. This is in fact what Ilford use in their paper cutting area although at a very low intensity.

Paterson/Photax had to introduce a VC (brown) dome for their safe-light in the late 1980's to counter this issue with their orange /red domes.

Ian
 
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