I have a theoretical problem: What are good lamps for lighting up a modern photo gallery?
I'm thinking of high-CRI blue chip based LEDs, as the even-higher-CRI violet LEDs could deteriorate photos quicker.
A fixture design I have thought of would be a long box, with a window at one end, and the photo at the other.
You would look thought the window, and there would be a square "ring" of LEDs around, so you wouldn't see them.
The LEDs would shine their light at the photo at the other end.
How much deterioration can occur from using violet (or blue) LED lighting?

Are you designing a sort of handheld display device ? If so what is the power source ?

As far as lighting is concerned, the amuount of deterioration depends on the materials in the artwork, brightness at different parts of the spectrum, and how much time the light is on. Some Plastics have been known to visibly discolor within months from exposure to White LED light (actually, to the Blue in it) at very high brightness, and would deteriorate at different speed at lower brightness. Incidentally the piece made of said Plastic was the lens panel of the LED luminaire, and it is somewhere on LG.. Many other materials would not care as much. I would imagine that Blue or Violet are less evil than UV, which means that for this application LED would be better than HID or Fluorescent

But there is also deterioration that would happen anyway (for the most part, materials of the artwork decaying by themselfes or reacting with Oxygen from the air), that can be slowed down by lowering the temperature and controlling moisture. So it is not known whether the lighting will be the thing that would damage the artwork the fastest at all

Museums and galleries that want to preserve valuable artwork use dimmed Incandescents, or dimmed Halogens with measures in place to block any remaining UV. Some of Europe's known museums went LED now, but i think they might have done this at the expense of the lifetime of the artworks presented

I would expect these to be lit ~12 hours a day.
The problem with dimmed incandescents is that they have too low of a color temperature.
I would use daylight (5000K - 6500K) LED lights, likely the SMD kind on a board.
This viewing device would be mounted (recessed) in a wall, so you would have to have an access room in the back, or pull it out for service.
There would be a relatively high brightness inside.
The power source could be almost anything, so you might need space to mount a power supply somewhere.

I still dont know much about the artwork, what it is made of and sizes/dimensions..

The power source i asked in the sense of - If it would be a handheld device, then would it be a battery - in which case the power available is limited. If it uses AC power then we are not limited in lamp choices from this side

If the artwork is indeed sensitive to UV or other light, is there way to minimize the lighting time ? Switch on the light only when somebody is looking at it ?

It could be lots of sizes, but the most likely size would be 8.5 x 11 inches ("Letter").
Maybe put UV protective glass in front of it?
The photo would be printed with good/great quality photo paper.
I assume it would be printed using dye ink, which isn't the best for UV resistance.
A motion sensor could be good, but it would look cheesy if you were looking at all of them, with people making them flash on and off.

If the work in display is photography, you could use whatever light source you like, as you could make reproductions and store the originals in a safe place. You would only need to scan the original (or negative if available) once in a computer and print as many prints as you want to replace them when they fade. Some museums do this on a regular basis.

If the work in display is photography, you could use whatever light source you like, as you could make reproductions and store the originals in a safe place. You would only need to scan the original (or negative if available) once in a computer and print as many prints as you want to replace them when they fade. Some museums do this on a regular basis.

That's a good idea that I didn't think of.
I also have a less theoretical question/problem: Is it safe to use pigment-based inks in a normally dye-based printer?