Diffusion material for print view area

[NeilPrintArt]

Hello!
I am wondering if anyone has experience or knowledge regarding the use of some kind of light diffusion material that won't affect the colour temp of the light it is diffusing?
I am busy upgrading my print viewing area and have invested in good quality (GTI Graphiclite) D50 fluorescent tubes. I have installed the tubes above my print view table and the quality is great. But I was hoping to soften and spread the light by putting some kind of lighting diffusion/filter in front of the lights? But I obviously don't want to affect the colour temp of the D50 tubes.

Also, regarding the lux (intensity) of the light in the view area, I have read that around 500 Lux is a good value to aim at? Is that correct? At the moment I am getting about 600 lux in the middle of the table and down to around 400 lux around the edges. So my thought was to soften and spread the light and also minimize reflections when looking at gloss paper.

any advice gratefully received, thanks very much

Neil

   

[digitaldog]

I'd contact GTI (maybe speak with Robert) about what is ideal for diffusion.
There is no 'correct' Lux per se. There are some recommendations based on standards for the print industry and GTI has a few PDF's about this on their site. But what you're dealing with is fine as long as you understand you will need to control the lighting and that the display calibration cd/m^2 you pick IS based on the viewing conditions so you'll have to adjust to match:

[deanwork]

Rosco diffusion gels. Neutral, various densities available, very tough, and won’t melt from most heat sources.

You can buy in rolls or 20x24 and smaller sheets from their website or see samples from any theatrical supply. Back in the days when we had photo supply stores they all had them.

https://www.stagelightingstore.com/808706-roscolux-gel-cleardiffusion

Hello!
I am wondering if anyone has experience or knowledge regarding the use of some kind of light diffusion material that won't affect the colour temp of the light it is diffusing?
I am busy upgrading my print viewing area and have invested in good quality (GTI Graphiclite) D50 fluorescent tubes. I have installed the tubes above my print view table and the quality is great. But I was hoping to soften and spread the light by putting some kind of lighting diffusion/filter in front of the lights? But I obviously don't want to affect the colour temp of the D50 tubes.

Also, regarding the lux (intensity) of the light in the view area, I have read that around 500 Lux is a good value to aim at? Is that correct? At the moment I am getting about 600 lux in the middle of the table and down to around 400 lux around the edges. So my thought was to soften and spread the light and also minimize reflections when looking at gloss paper.

any advice gratefully received, thanks very much

Neil

   

[Peter McLennan]

Shower curtain material.  Found on movie sets world-wide.  Tens-of-thousands-a-week Cinematographers probably aren't wrong.

WAY cheaper than Rosco and just as effective and colour temperature friendly.  If it looks white, it is white.

Rosco exists because some applications demand absolute batch-to-batch consistency.  Yours doesn't.

[digitaldog]

If it looks white, it is white.

Ouch... "Extraordinary claims require extraordinary evidence."-Carl Sagan
The question (and the answer is to measure with a Spectrophotometer:  diffusion material that won't affect the colour temp of the light it is diffusing?
So it might be spectrally neutral but it might not, no matter how it 'looks' and there's one way to know.

[deanwork]

I’m pretty certain that the color temp neutrality for shower curtains made in China are carefully checked for
consistency, just in case someone in the US might decide to utilize them for critical photographic applications.

Ouch... "Extraordinary claims require extraordinary evidence."-Carl Sagan
The question (and the answer is to measure with a Spectrophotometer:  diffusion material that won't affect the colour temp of the light it is diffusing?
So it might be spectrally neutral but it might not, no matter how it 'looks' and there's one way to know.

[digitaldog]

I’m pretty certain that the color temp neutrality for shower curtains made in China are carefully checked for
consistency, just in case someone in the US might decide to utilize them for critical photographic applications.

Yeah that makes perfect sense. What was I thinking? 

[Peter McLennan]

With respect, I think you guys are overthinking this.  It ain’t rocket science, it’s photography.

[digitaldog]

With respect, I think you guys are overthinking this.  It ain’t rocket science, it’s photography.

No its not photography, it's a viewing booth for prints. There are defined ISO specification on this kind of stuff if you want to take it seriously:
https://www.gtilite.com/why-standard-viewing/

[Ernst Dinkla]

I’m pretty certain that the color temp neutrality for shower curtains made in China are carefully checked for
consistency, just in case someone in the US might decide to utilize them for critical photographic applications.

I recommend the Premium Baryte shower curtain !


Met vriendelijke groet, Ernst

http://www.pigment-print.com/SpectralPlots/SpectrumViz_1.htm
March 2017 update, 750+ inkjet media white spectral plots

[JRSmit]

I recommend the Premium Baryte shower curtain !


Met vriendelijke groet, Ernst

http://www.pigment-print.com/SpectralPlots/SpectrumViz_1.htm
March 2017 update, 750+ inkjet media white spectral plots

And stretched ,but under 45degrees ;-)

I tested diffusion filters of Lee and that worked to get more diffuse lighting without significant altering of spectrum, it reduceert the lighting level obviously. But i am not certain it is the right direction to go. It is not equivalent to f.i. the situation when hung on a wall, lighting is on a greater distance, therefore more directional.

[PeterAit]

I'd just hang a single or double layer of cheesecloth.

[deanwork]

Cheesecloth or any fabric has some degree of color cast. And they vary from roll to roll and certainly will easily  change over time.

I have one of those GTI Desktop print viewing units that I got a good deal on, but it has no dimmer switch.

So I tried to plug it into a dimmer designed for fluorescents that I got from Home Depot. That didn’t work.

I ended up taping a rosco neutral diffusion gel over it. That worked great for matching the brightness of my display and the color was not changed. I only used one but you could layer less dense gels to match any subtle intensity.

Buy the way these gels don’t seem to shift color even after many years. I have some that are 30 years old that I used to use for 1000 watt hot lights and even when stored in terrible conditions have not changed. Biggest bang for the buck I’ve ever spent. If you can’t afford these, I don’t think you can afford to make prints.

John

I'd just hang a single or double layer of cheesecloth.

[NeilPrintArt]

Thanks everyone ! This is great

[elliot_n]

Lee or Rosco 216. (You'll probably only need one or two sheets, so cheaper than a shower curtain.)

[PeterAit]

Now that I think about it, I agree with the poster who said this is being way over-thought by the OP. The people who view your photos won't give a fiddler's fart whether they match your display exactly. And they will be viewing them in different light conditions. Now, if you like fiddling with color balance and all that, fine. but that's not photography.

[digitaldog]

Now that I think about it, I agree with the poster who said this is being way over-thought by the OP.

It's clear you do because you haven’t read what the OP is trying to accomplish and with what product. Try thinking about that....

The people who view your photos won't give a fiddler's fart whether they match your display exactly.

They do not. But the OP does. And part of that process, which isn't clear to you, is controlling the print viewing conditions and, the color temp of it, as well as many other attributes play a role in that.
IF you study this a bit more, it might be a bit more clear to you and a few others:
http://lumita.com/site_media/work/whitepapers/files/calibrating_digital_darkroom.pdf

[NeilPrintArt]

My feeling is that there certainly is something to be said for not getting too worried about 'numbers'. The majority of prints are not going to be viewed in ideal lighting situations anyway, in fact they will be probably be viewed in a vast array of different lighting - ranging from offices and homes to 'galleries' with lots of windows etc. So why bother spending time and money creating a 'print view area' that matches (approximately) some ideal 'number' - in this case D50? My answer is that I want to work in a controlled environment and to eliminate as many variables as possible. A fixed starting point makes it easier to control the outcome.

I suppose it also depends who you are printing for? If one is only making prints for oneself or if one is printing for a variety of clients?

The most immediate difference I have noticed since installing proper D50 lighting is how markedly different 'paper white' appears. The difference between 'warm' and 'bright' paper is dramatic.   

[digitaldog]

The most immediate difference I have noticed since installing proper D50 lighting is how markedly different 'paper white' appears. The difference between 'warm' and 'bright' paper is dramatic.   

Yup, and if the papers have OBAs, the differences can be dramatic.

[Doug Gray]

Yup, and if the papers have OBAs, the differences can be dramatic.

True, so long as the "D50" isn't gelded (low or no uV).