Making UV pics brighter in UV light

[Daniel354797073000]

Hi Friends,

I didn't have a better idea where to post this question.

I am trying to find a way to predict how much glow a picture will be under UV light.

From what I understood, only Yellow, pink, green and blue are good to print and glow under a UV light. 

I'm also sure that not all shades of these colors above are good for this purpose, only some.

So...

I am trying to find a way to :

1. predict using photoshop how much glow a photo is producing under a UV light

2. Change a bit the shades or colors if neceery, to make it glow even more. 

Do you have an idea how to do it? Or where to post this question?

Thank you very very much 

[D Fosse]

The name for this is UV fluorescence.

It means that some pigments/dyes will emit visible light when hit by ultraviolet (invisible) lighting.

This is specific to each fluorescent substance (molecule) and there are no common rules governing the effect. In other words, it's unpredictable. Fluorescence is quite weak and requires long shutter speeds (and a dark room with UV light sources). 

I do this at work (photographer at art museum), so I have some experience with it. We use infrared and ultraviolet photography in several standardized procedures, and UV fluorescence is one of them.

[didiermazier]

You could try to find and load a LUT file (i.e. https://creativemarket.com/SparkleStock/7074310-25-Ultraviolet-Lightroom-Presets-LUT) and apply Image>settings > color matching on a smart object

search google with "UV light LUT"

 

[D Fosse]

These LUTs/presets seem to be for making a normal photograph look like it was shot in UV light.

A photograph taken in actual UV light doesn't require much additional processing, except for providing enough exposure to the shot. What you're capturing is normal visible light, so you don't need a UV modified camera either.

Usually, UV fluorescence will be mostly on the blue end of the visible spectrum - in other words, the blue-sensitive sensor pixels get the most exposure. To balance this, you can use a strong yellow filter and increase the exposure. I use one of those standard yellow filters that were used in black and white photography to darken blue skies and increase general contrast, can't recall off the top of my head what it's called.

[didiermazier]

So maybe it would be possible to create a specific LUT to check what the image would show under UV light…

I will ask to some VFX artist, they are used to these checking tricks things.

[Daniel354797073000]

Thank you, I would love to know if that is doable .  Like in example photo, I am sure there are some modifcations that could have been made, using photoshop, before actually prinitng it, to enhance the glow effect, in most areas of the image 

[Semaphoric]

How will you be printing this? Maybe you could use fluorescent inks.

[D Fosse]

@didiermazier 

But it's inherently unpredictable unless you know which dyes/pigments have been used and the chemical composition, and you know how those compounds behave under UV light.

[didiermazier]

so the only remaining solution seems to buy a checker…

https://www.quicktest.co.uk/blogs/testing-ultra-violet-magnets/all-about-ultra-violet-testers

[Daniel354797073000]

They use special inks , the question is how to predict what shade of a color will glow brighter, once printed .  This is the original image, as you can see, there are many areas of green, for example, but not all of the greens glow in the same intensity . That's what I am hoping to figure out  

[Lumigraphics]

Fluorescent inks have optical brighteners added, so they react under specific wavelengths of light. These brighteners can be found in some clothing dyes and laundry detergents as well. There is no sure way to predict how they work, and even different brands of lights can give a different effect.