canon Lee

Since a previous thread about this subject, I contacted Hoya a lens filter company, & asked them which one of their filters would correct the saturated hot spots that appear in the shot.
Here is what they sent back.

Thank you for contacting us.

We would like to inform you that the filter ( UV) may be not eliminate the over saturation and hot spots.

If there is reflected light on a T-shirt overall, the Cir-PL filter is effective.
If there is much whole light quantity, I would recommend to use the ND filter.
Please consider to fade by the soft filter, if there is spot-like light.

Thank you for your continuous support.

Best regards,
Ken H.
Tokina/HOYA supporting unit, Kenko Tokina Co., Ltd

So I looked up cir-PL filter (http://www.hoyafilter.com/hoya/products/hdnanofilters/hdnanocirpl/) Some how I am not convinced this would work. appreciate any remarks.
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jerryc41 Loc: Catskill Mts of NY

They certainly aren't going to tell you not to buy a filter. Looking at your original post and the responses, it seems like a problem. Have you tried educing Highlights in LR? As GoogyNewfie pointed out, the problem is with the color of the shirt itself.

canon Lee

Hi Jerry. From what I have researched, the inks that are used for glow or neon interact with the UV light band that comes from the light source. The interaction causes the neon to become brighter creating hot spots and color shifts as well as over saturation. LR has been a life saver in post production. I am sure that a UV filter on camera, along with UV gels on the light source would reduce the brightness of the shirt. BUT, I do Picture day for 100 or so kids and have no time to add gels and filter. So I will continue under exposing, looking at my histogram, and tweak in PP.

GoofyNewfie Loc: Kansas City

Despite the effort to fix this issue, in the end most parents probably won't notice the color issue, just the expression.
Some of us are our worst critics.
I like to get everything right, but sometimes done is good.

Leitz Loc: Solms

Given the conditions you're working under, this sounds like your best option.

canon Lee

You are so correct. I am a very anal person and notice way too much. LOL

GoofyNewfie Loc: Kansas City

I hate to compromise on some things.
If it were an art piece, yes, but this isn't art.

blackest Loc: Ireland

http://surlyteabag.blogspot.ie/2009/04/what-makes-neon-colors-look-neon.html is interesting to sum up the flourescent colors take light of one frequency and emit it at a higher frequency.

If you are using flash then you need to block the stimulating frequency light. maybe a UV filter over the flash head would help?

Polarising filter on the lens might attenuate the day glow colors.
maybe a warm filter sheet on the flash might help although it's going to mess with skin tones.

If you have a uv filter perhaps you can tape it to the flash head and see if it has an effect. If it really is blocking uv then the shirts should tone down a little. Good luck finding a solution.

jelecroy Loc: Huntsville, AL

I don't think a UV filter on the camera lens will have any helpful effect. When UV light strikes a phosphorescent surface, the phosphors absorb the UV and re-emit energy in longer wavelength visible colors. There probably isn't enough UV light coming from your subjects to make a difference in imaging.

If you are using flash, a UV filter over the FLASH head might be useful. That would reduce the UV from your flash hitting the day-glo surfaces. But I doubt seriously that is actually your poblem.

It seems likely to me that what you are fighting is not phosphorescence, but rather retro-reflectance. Many kids garments have retroreflective materials coated on, mainly for safety reasons (so car drivers can see them at night). You can think of the retro-reflective stuff as little glass beads, like on a slide projection screen, or a traffic sign. They have the special optical property that light hitting them reflects back mostly in the direction exactly opposite to the arrival vector - that is right back at the source. If you are using on-camera flash that reflected light is the almost certainly the sources of your image quality problem. It is easy to correct. Here are some options:
1. Turn off the flash altogether and use available light. This approach is cheap and will give you the most natural-looking result. It will also eliminate those nasty thin shadows below stuff in the pictures.
2. If you feel like you have to use flash, use a hot-shoe mount with a rotate-able head, and rotate the head to point at the ceiling. That way the light from your flash reflects off the ceiling, which will illuminate your subjects more normally.
3. Use two or more off-camera strobes, and trigger them with RF from your camera. I have done this many times, mostly using strobes with either umbrellas or soft boxes to spread out the light source so I don't get hard shadow edges on my subjects. This is the pro approach, but requires schlepping and setting up a set of portable studio-style strobes.
4. It's possible to use smaller strobes like a pair of Nikon SB-5000 AF Speedlights mounted on tripods. The off-camera lights can radio-trigger from the camera. Because the small lights are pretty much point sources, they will create un-flattering shadows, and you will occasionally miss a shot because you trip the shutter while the battery-powered flashes are still re-cycling. A pro flash set with AC-power (like in option 3) will recycle almost instantly, so you don't miss shots.

Hope that this helps.

jerryc41 Loc: Catskill Mts of NY

Exactly right! If a parent complains about the shirt, that's an insult to his kid.

canon Lee

Thank you for taking the time to share with me. I use 2 1600W monolights/umbrellas, triggered by radios. I set the lights at almost full and adjust aperture/shutter accordingly, slightly underexposed whites. We shoot indoors where the ambient light is from gym lighting. So I am not sure how much UV ambient light is there. Not sure how to affix a UV filter gel to the lights without over heating. I know that when using polarizing filters/gels for the camera as well as the lights, will attenuate glare. That would take care of the hot spots. but its the lack of detail in the shirt overall. The shirts are florescent and its not the lettering as in stops signs. I suppose I will have to buy a UV filter for my lens ( Canon EF24~105 L) and try it out. Personally I feel it will have a minimum effect for a $50~100 UV filter. I am surprised that not one photographer here has had any real life experience with glow shirts ( but I think most aren't commercial photographers). Lots of differing opinions though, which is helpful.

blackest Loc: Ireland

I don't see how a uv filter at the lens would help. It's not too much uv at the lens but too much uv at the shirt.

Consider an episode of csi bu illuminating with a blacklight it stimulates production of visible light. Maybe for an experiment mount a uv filter in a snoot try a couple of shots with and without with the same settings. If it's effective at all the neon should be darker.

If successful maybe these people could help

http://www.grayglass.net/glass.cfm/Gray-Glass/Devon-Theatrical-Lighting-Filters/catid/5/conid/5