Luminous Landscape Forum
Raw & Post Processing, Printing => Printing: Printers, Papers and Inks => Topic started by: NeilPrintArt on January 07, 2020, 12:06:49 pm
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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
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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:
(http://digitaldog.net/files/Print_to_Screen_Matching.jpg)
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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
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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.
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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.
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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.
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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? ::)
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With respect, I think you guys are overthinking this. It ain’t rocket science, it’s photography.
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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/
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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
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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.
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I'd just hang a single or double layer of cheesecloth.
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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.
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Thanks everyone ! This is great
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Lee or Rosco 216. (You'll probably only need one or two sheets, so cheaper than a shower curtain.)
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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.
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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 (http://lumita.com/site_media/work/whitepapers/files/calibrating_digital_darkroom.pdf)
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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.
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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.
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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).
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Well if we want to get real picky, there's only one D50 (which is an average of many measurements made all over the planet) and it's source is 93 million miles away. :D
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. . . 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 (http://lumita.com/site_media/work/whitepapers/files/calibrating_digital_darkroom.pdf)
Andrew,
Thank you for this reference! I’d not come across it before. It validates/reinforces some of my “over thinking” in regard to my editing space. 🤓
Others - While it is true that we cannot know/control the lighting conditions under which our work may ultimately be displayed, why wouldn’t we want to get is “as right as possible” and “the way we want our work to look” as the starting place? Based on the illogic of the “we can’t know” position, why color manage at all? Any print would be “good enough.” It seems odd to me that we’ll “measurbate” endlessly on selecting VERY expensive cameras and lenses and argue about minute differences, then swallow a camel in the “don’t overthink” department with our final product / output. I don’t get it.
Rand
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Andrew,
It seems odd to me that we’ll “measurbate” endlessly on selecting VERY expensive cameras and lenses and argue about minute differences, then swallow a camel in the “don’t overthink” department with our final product / output. I don’t get it.
Rand
This argument parallels that of "don't use third party inks". I refuse to submit to marketing bafflegab. I do tests and make up my own mind.
I watched numerous highly-paid Hollywood cinematographers use various diffusion materials on set for decades. Their multi-million dollar projects and their own professional reputations were on the line. As was mine when I used similar materials with similar results.
The proof is in the results, not the rules-based approach. The human vision system is astoundingly complex.
https://www.amazon.com/Vision-Updated-Expanded-Margaret-Livingstone/dp/1419706926/ref=sr_1_1?keywords=the+biology+of+seeing&qid=1578675380&sr=8-1
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This argument parallels that of "don't use third party inks". I refuse to submit to marketing bafflegab. I do tests and make up my own mind.
I watched numerous highly-paid Hollywood cinematographers use various diffusion materials on set for decades. Their multi-million dollar projects and their own professional reputations were on the line. As was mine when I used similar materials with similar results.
The proof is in the results, not the rules-based approach. The human vision system is astoundingly complex.
https://www.amazon.com/Vision-Updated-Expanded-Margaret-Livingstone/dp/1419706926/ref=sr_1_1?keywords=the+biology+of+seeing&qid=1578675380&sr=8-1
I agree. I don't see any argument/disagreement in what you've said. And I don't see Andrew's comments (or mine) as "rules-based." It just seems to me that starting off with "known," controlled values is the best place from which to depart as you see fit, once you have a feel for what you're doing. I'm certain that your own creations were not just random with no thought to the desired outcome and consistency of look across the project. So for someone like the OP, starting out to setup standard viewing conditions for his work, it seems logical to use "known" values / materials. No "rules" there, I don't think, just the logical straightest line between A and B.
Rand
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It seems odd to me that we’ll “measurbate” endlessly on selecting VERY expensive cameras and lenses and argue about minute differences, then swallow a camel in the “don’t overthink” department with our final product / output. I don’t get it.
You usually hear this from people that make assumptions about color, have no tools to measure it, use a made up term to dismiss the concept of measuring things etc. Or a quote might help too:
"I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind."-Lord Kelvin
Do ask those who knock measurements if they've ever used a light meter. That might shut them up from making preposterously silly claims!
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The reason we have standards is because it allows us to communicate with each other. Those of us who have clients to communicate with weekly know the value of seeing the same hues, contrast, and brightness content at the same time so we can do that. That’s elementary and without that base point you don’t have a chance. But even my most amateur photographically unsophisticated clients understand that.
Edward Weston photographed without even a basic light meter, because for the most part he shot the same subject matter with the same camera, lens and film for his whole career, and he had no money. That doesn’t mean it is smart to turn off the light meter on our dslrs. I do believe this thread has gone way beyond its usefulness.
You usually hear this from people that make assumptions about color, have no tools to measure it, use a made up term to dismiss the concept of measuring things etc. Or a quote might help too:
"I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind."-Lord Kelvin
Do ask those who knock measurements if they've ever used a light meter. That might shut them up from making preposterously silly claims!
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And with the “Sunny 16” rule at least for some films, you don’t need a light meter.
But I highly suspect, most of those who look down on color measurements and call it a silly name, measure all kinds of other attributes including light.
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And with the “Sunny 16” rule at least for some films, you don’t need a light meter.
But I highly suspect, most of those who look down on color measurements and call it a silly name, measure all kinds of other attributes including light.
If your reply is directed at me, I don't "look down on colour measurements". In fact, I carried several light-measuring instruments throughout my career and used them carefully.
In addition to being one of those Hollywood cinematographers who used Rosco and Lee products extensively, I hold a (Canadian) National Diploma of Technology in Instrumentation and Control Systems. I understand the need for measurement standards.
I also subscribe to the axioms that "Everything should be as simple as possible, but not simpler" (Einstein) and, "If it looks right, it probably is right" (Me)
My reaction to the original poster's question was based on the assumption that he'd have to buy an entire roll of Rosco material in order to solve his problem. An unnecessary expense, IMO.
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My reply was in general to those who accuse others that they ” measurbate“. Nothing more.
Simple can be good, but....
"For every complex problem there is an answer that is clear, simple, and wrong." H. L. Mencken
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All I can say is if you thought he had to buy a entire roll of rosco diffusion gel for such a tiny job then you know pretty much nothing about lighting, degree or no degree, it’s been the same for at least 35 years.
If your reply is directed at me, I don't "look down on colour measurements". In fact, I carried several light-measuring instruments throughout my career and used them carefully.
In addition to being one of those Hollywood cinematographers who used Rosco and Lee products extensively, I hold a (Canadian) National Diploma of Technology in Instrumentation and Control Systems. I understand the need for measurement standards.
I also subscribe to the axioms that "Everything should be as simple as possible, but not simpler" (Einstein) and, "If it looks right, it probably is right" (Me)
My reaction to the original poster's question was based on the assumption that he'd have to buy an entire roll of Rosco material in order to solve his problem. An unnecessary expense, IMO.
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All I can say is if you thought he had to buy a entire roll of rosco diffusion gel for such a tiny job then you know pretty much nothing about lighting, degree or no degree, it’s been the same for at least 35 years.
The degree never formed a part of my career. I did work as a cinematographer for several decades. I'm on IMDB, if you care to look there.
In my market, there's no way to purchase a few feet of Rosco materials. Full rolls only. Unless you know someone on the grip truck.
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Peter,
Rosco has always sold 20x24 sheets of the diffusion material that you can cut down as well as smaller sheets from all of my past experience.
You can also receive a swatch book of everything they make for free.
John
The degree never formed a part of my career. I did work as a cinematographer for several decades. I'm on IMDB, if you care to look there.
In my market, there's no way to purchase a few feet of Rosco materials. Full rolls only. Unless you know someone on the grip truck.
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Thanks, John. I must have a few old Rosco swatchbooks sitting around in drawers. Never seen sheets for sale in my market, though.
Not that I cared. I never had to purchase them, I just asked the grips. :)
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Could this be as simple as "Hollywood supply houses don't stock smaller sheets of Rosco material, because movies use a lot of lights"?
B&H has all sorts of sheets of Rosco material, including neutrals (cheap, too) - but I wouldn't be surprised if AbelCine and friends didn't bother?
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This is nice, if they fit. Otherwise a 20x24 sheet which is much cheaper will work.
https://www.amazon.com/dp/B00NVXWLAU?ref_=pgi_2h3d2n3e4a350ai35ai63l7cdamh&tag=vzcmapper-us-20&ascsubtag=pgi-P04-V01-05-X92-LO-T1R3AT
B&H has all sorts of sheets of Rosco material, including neutrals (cheap, too) - but I wouldn't be surprised if AbelCine and friends didn't bother?
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