Color Adjustments for Photos that will Display under Florescent Lighting

How long is a mural usually supposed to be on display? 

If years or above the aging of the prints themselves could add yet another degree of unpredicability. 

One challenge is that fluorescent lamps come in many variations (cool white? warm white? high CRI?), so if you don’t know exactly what lamps they have installed, you might be guessing wrong. So it is a good idea to try and get more specific info about the room.

As suggested, one way is a technical solution involving measurements of the room lighting, and turning that into a profile you can soft-proof against using the ICC profile of the intended ink/substrate combination. But, you have to have the hardware, software, and some level of expertise, and every part of the capture-to-print chain has to be set correctly for all the numbers to work right.

So the other, much simpler way to do it is…

Acquire advance access to the customer’s installation site, bring a test print made on the intended ink and substrate combination, and view it under the lighting in that room. Indicate corrections as needed, then come back with an updated test print to see if that one is good enough.

Long term, a potential flaw with both methods is that exact color reproduction depends on the specific lamps installed in the fixtures. Less of a problem for museums, bigger problem for general buildings where lighting isn’t tightly controlled. If you get it perfect for the room as it is today, and then a few months later someone calls in a crew to replace some or all of the fluorescent lamps, and the replacement lamps have a different color temperature or spectral response, the photo mural may look slightly different. Or, someday they decide to upgrade the building to LED lighting with a completely different color temperature, CRI, and spectral profile! The lighting might change in the future, outside of your control. But it won’t just be you…it’s been this way for almost every photo mural ever installed, even years before we had precise digital control over print color.

This is tricky! The eye adapts very effectively to ambient light, and I suspect any attempts at "full correction" will only make it worse. If a white piece of paper still looks white in this lighting, it's probably best to not do anything.

However, the most immediate problem is not overall ambient light color, but uneven and spiky spectral distribution. Fluorescent light is very spiky, and as a result some colors will "disappear" to varying degrees, or appear darker than they should. Others will be more prominent.

This is actually a very parallell situation to camera profiling. This is why you'd make special camera profiles for special lighting, shooting a colorchecker and running it through profiling software (dng profile editor/x-rite etc) to make a camera profile. Fluorescent lighting and LED are prime candidates for this.

Off the top of my head I don't know how you would approach this. I'm sure it's possible, the problem itself is pretty well defined, so I'm sure there are solutions out there.

You would have to either take a reading of the light value in the room your images will be shown and adjust accordingly in Photoshop or you can use the Camera Raw filter to adjust your White Balance to Fluorescent.

They would look odd on screen, but when output they would compensate for the lighting.

My only concern is you say it is a green light hue - most fluorescents are magenta, cyan or yellow cast - hence why I would opt to get a color reading or shoot a gray balance card in the room for reference.