Color shift from reading/computer glasses?

[Ernst Dinkla]

I use plain old CR-39 plastic lenses with Crizal Advance AR coating. No color problems. But do a test. I do it with every pair of glasses I get.

Put the glasses on a neutral gray card and fire some shots. Shoot slightly out-of focus. Make several shots with light at different angles to the glasses. Process shots, white balance on the area of the gray card outside the glasses. Read the RGB values inside the glasses.

Should tell you if the glasses are adding any color cast.

I've been getting interested in "blue blockers" for computer glasses. Went in a local shop and looked at the Zeiss version, called "BlueProtect". Those definitely had a color cast, obvious to the naked eye. Is it possible that's what you got? I thought Zeiss "Office" was all about balancing different viewing distances, not blue blocking. But not sure.

Basic rules in color science would suggest that in a dark room and you looking at the monitor and your glasses put on the monitor + a large PS window with neutral greys should be enough. One and the same observer for the test and the practice. If within the glasses area the greys show a color shift you have a problem. A problem that may be extended when you look at your print in monitor suited viewing light with the same glasses. I asked for the most neutral coating for my computer glasses and I do not see a shift.

However; last spring my eye doctor told me that my eyes show a light form of cataract so the yellow shift is setting in at snail's pace. For 50% of today's photographers that may be a thing to consider too. Whether a glasses coating could compensate that till the inevitable surgical step clears up our sight again is something I do not know. But I am sure cataract is an underestimated factor in the color estimation of many photographers.

At some point we have to trust our spectrometers/color checker/white calibration targets more than our eyes, color editing by the eye may be the weakest link in this chain. The more when the original subject of the image is not at hand but 5000 miles away. A camera is not a suitable spectrometer/colorimeter though.


Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
January 2016 update, 700+ inkjet media white spectral plots

[GWGill]

Seriously though, I'm not sure this is overblown at all. The fact that our own eyes adapt does not seem relevant when it comes to producing an end product that will be viewed by others. If we are the only ones who view our own work, then yes, it is irrelevant. Otherwise, it seems to me, the color shift produced by glasses is as relevant as any other step in the color management chain.

Not at all - Adaptation is a fundamental characteristic of human vision. The classic experiment is to pop one of the lenses out, and then put the glasses on for 10 minutes. At first you will notice an obvious difference when closing one eye or the other, but by the end you won't.

[N80]

Not at all - Adaptation is a fundamental characteristic of human vision. The classic experiment is to pop one of the lenses out, and then put the glasses on for 10 minutes. At first you will notice an obvious difference when closing one eye or the other, but by the end you won't.

I'm not sure how that applies to image editing. If I edit an image through glasses that yield a warm tint then I will adjust the image from an artificially warm starting point that will probably not be the same starting point for most viewers. It would be no different from an improperly calibrated monitor that was calibrated too warm. Now, this might be nit picking but if it is, then so is most of the other stuff we struggle with when trying to achieve some level of 'proper' calibration and print output.

[Alan Klein]

It's good to know that they've not gotten rid of the useless blurry area at the sides of the vision field on the progressive lenses.  I tried them a couple of times in the mid-2000's and that was my problem with them.  Your experience has saved me another potentially expensive experiment.  The opticians who sell them always say "Oh, they're much better now than they used to be!"

So what do you wear?

[N80]

I can't speak to what they were like 15 years ago. But, I've got Silhouette brand progressives ($$$) with what appears to be three bands of focus, near, medium, far. It took me a few weeks to get used to them including moving my head to line them up. But, since then I've had no problem with them outside of typical glasses problems (rain, sweat, falling off, getting scratched, bridge of nose fatigue,etc). I've had them about 3 years.

Mine are extremely light which is nice. The lenses are stylishly small but other than looking good a small lens seems to have smaller 'bands' of focus which can require more head and eye movement. I did not notice this until I got prescription sunglasses that are Ray Ban Wayfarers with great big lenses. The sun glasses are far more pleasant to use because the focal bands are broader. I'm due for a new pair of every day glasses. I will get larger lenses this time, I really don't care about style. I will also decline the anti-glare coating for computer use since I can't see much benefit and as mentioned they do give things a warm cast.

I am also very interested in the Zeiss 'indoor' glasses optimized for reading and computer use. Another huge expense but when it comes to my eyes I'm willing to pay.

[GWGill]

I'm not sure how that applies to image editing. If I edit an image through glasses that yield a warm tint then I will adjust the image from an artificially warm starting point that will probably not be the same starting point for most viewers.

We don't have an absolute reference - our vision adapts to the overall white point of what we see. Typically it will be something close to the white point of the image. If an image looks warm, it is because mid tone's are warm compared to the white point. This will be true even if our absolute white point is shifted one way or the other.

It would be no different from an improperly calibrated monitor that was calibrated too warm.

The absolute white point of the monitor doesn't make it look warm or cold in isolation. It's only by comparing it with something that it looks so. Typically we say a display looks warm or cold because its mid-tones deviate from the chromaticity of its white point, so it is this aspect that is most important in calibrating a display, not the absolute chromaticity of the white.

[Bart_van_der_Wolf]

We don't have an absolute reference - our vision adapts to the overall white point of what we see. Typically it will be something close to the white point of the image. If an image looks warm, it is because mid tone's are warm compared to the white point. This will be true even if our absolute white point is shifted one way or the other.

The absolute white point of the monitor doesn't make it look warm or cold in isolation. It's only by comparing it with something that it looks so. Typically we say a display looks warm or cold because its mid-tones deviate from the chromaticity of its white point, so it is this aspect that is most important in calibrating a display, not the absolute chromaticity of the white.

Hear, hear.

Human vision is not that good at nailing absolute values, it has evolved to do a decent job of comparative judgments.

Due to the limitations of human vision in processing everything, it is a system that avoids signal overload and only picks up significant differences from the (local) average.

Cheers,
Bart

[N80]

How is any of that relevant to the point at hand which is glasses with a color tint that are worn while doing color management. It is the equivalent of putting a large tinted filter in front of your monitor, right?

[StarScapes]

We don't have an absolute reference - our vision adapts to the overall white point of what we see. Typically it will be something close to the white point of the image. If an image looks warm, it is because mid tone's are warm compared to the white point. This will be true even if our absolute white point is shifted one way or the other.The absolute white point of the monitor doesn't make it look warm or cold in isolation. It's only by comparing it with something that it looks so. Typically we say a display looks warm or cold because its mid-tones deviate from the chromaticity of its white point, so it is this aspect that is most important in calibrating a display, not the absolute chromaticity of the white.

Great explanation! The coatings must affect the brightness to some degree too. Do we also adapt to that difference?

[Tim Lookingbill]

How is any of that relevant to the point at hand which is glasses with a color tint that are worn while doing color management. It is the equivalent of putting a large tinted filter in front of your monitor, right?

There are sort of two types of adaptive influences on perceived white balance when processing images that follows what GWGill points out. There is the filter effect most noticeable of the two as one single hue uniformly covering the entire image (eye glass tinting). And then there's cool/warm/green/red split tone effect that can mess up color constancy appearance ACR/LR's Split Tone attempts to correct. I'm often perplexed having to choose a yellow hue on the Split Tone slider to make purplish blue shaded tree foliage look neutral or warm but the RGB readouts don't indicate this, but it looks correct

On a display the brightness and color of white surround causes the viewer to see a neutral white quicker than lower less bright tones. Work on a sunset image and switch to a snow scene to see this. So it is harder to see the color of bright white and much easier to see the color of darker tones but if the bright white is slightly pink or greenish yellow and the viewer spends a long time in edits adapts to seeing it as neutral that will make subtle pastels such as an off white rock garden surrounded by mid tone grass and foliage appear slightly green (w/pink white) or slightly reddish blue (w/greenish yellow white).

Having tinted hued eyeglasses I would think would add another level adaptive complexity during long edits. I certainly wouldn't be wearing them checking screen to print matches.

[Tim Lookingbill]

And from what I've noticed with calibration software throughout the years D65/6500K especially with X-rites definition favors a slightly pinkish blue white over a greenish blue and that I believe has a lot to do with the software taming the green spike of backlit LED displays where green has a primary influence over luminance, definition and contrast appearance.

Some other brands of calibration software tend to go too far and make D65 white point target look too pinkish blue according to what I've seen of side by side comparison shots of calibrated displalys online.

[GWGill]

How is any of that relevant to the point at hand which is glasses with a color tint that are worn while doing color management. It is the equivalent of putting a large tinted filter in front of your monitor, right?

Exactly. It changes the absolute color of the white point, but because all the other colors are affected in exact proportion (it's a passive filter after all), and because our eye's will adapt to the white, after a while the filter will have little effect on our perception.
(There are limits of course - a gross change in white point will not be 100% adapted to, and this is particularly so if the shift is at right angles to the illuminant locus - i.e. not like a color temperature change.)

[N80]

I must be dense as I still don't understand how my adaptation to the change in white point caused by my glasses is relevant to the final output that someone else will be looking at, in all probability without glasses that have an effect on the white point?

Again, this would be no different from me starting with the wrong white balance and basing my adjustments on it.

Or else I'm missing something (which is fairly likely.)

[Doug Gray]

I must be dense as I still don't understand how my adaptation to the change in white point caused by my glasses is relevant to the final output that someone else will be looking at, in all probability without glasses that have an effect on the white point?

Again, this would be no different from me starting with the wrong white balance and basing my adjustments on it.

Or else I'm missing something (which is fairly likely.)

The glasses have a strong suppression around 400-460nm. This has a much smaller affect on wide spectrum sources such as high CRI CFLs and daylight compared to monitors which are based on tri-color, much narrower, spectra.  The result is that a monitor's white point will be impacted much more than the white point in a viewing booth. This will make proofing harder when viewing hard proofs side by side with soft proofs as the latter will be a much warmer color in comparison.

It will shift a monitor's white point from 6500K to a much lower Kelvin and possibly change the chromaticity to a more non-neutral level as well. It will make using a spectrophotometer to align soft proofing to hard proofing much harder if it's doable at all.

Fine for office work, not so good for good color control.

[N80]

That was my (uneducated) assumption as well. I have ordered a cheaper set of glasses without this particular coating on them and will see how they compare. Otherwise, on the rare occasion that white balance will be super critical in my work flow I will have to make initial white balance and color corrections with the glasses off.

[Tim Lookingbill]

That was my (uneducated) assumption as well. I have ordered a cheaper set of glasses without this particular coating on them and will see how they compare. Otherwise, on the rare occasion that white balance will be super critical in my work flow I will have to make initial white balance and color corrections with the glasses off.

If your glasses show a slight tint then I don't think this will be an issue, but we don't know how severe or dense the tint is to cause a noticeable shift in white appearance.

But in my experience with no tinted glasses editing long hours on my 6500K monitor when I switch to the slightly greenish warm tinted white paper viewed under 5000K T8 fluorescent tubes I notice ONLY the shift in white but not in the rest of the colors on the print.

If the tint of glasses is so dense to make both monitor and paper white and mid-range colors noticeably shift then I'ld see a problem.

The tint hue of the glasses would most likely be a major influence especially if it's slightly rose or magenta tinted compounded by the slightly pinkish blue of 6500K where the green channel has been pulled back influencing density the most. If it's slightly greenish yellow then you'ld get a neutralizing effect on the bluish 6500K white.

[N80]

I have not even tried looking at paper white with them on and off. I recently ran over them in the car and will probably not have that coating added to my next good pair of glasses. I could not tell any improvement in terms of working on the computer all day at work (I'm a doctor so that's all we do anymore).

The tint of the glasses look purplish when looking at the glasses. There is no perceived tint at all when looking through them. But when you compare how the monitor looks with them on verses off there is a distinct warm tint throughout the image.

Bottom line is, I will not add this coating for computer monitor glare to future glasses but I will be checking to see if the standard anti-glare coatings have any effect.

[Doug Gray]

I have not even tried looking at paper white with them on and off. I recently ran over them in the car and will probably not have that coating added to my next good pair of glasses. I could not tell any improvement in terms of working on the computer all day at work (I'm a doctor so that's all we do anymore).

The tint of the glasses look purplish when looking at the glasses. There is no perceived tint at all when looking through them. But when you compare how the monitor looks with them on verses off there is a distinct warm tint throughout the image.

Bottom line is, I will not add this coating for computer monitor glare to future glasses but I will be checking to see if the standard anti-glare coatings have any effect.

Anti-reflective coatings have no material effect. My glasses have AR coatings and the Lab value change is about 0.2 dEs.

While specular sources that reflect off my AR glasses have a slightly greenish tint the spectral absorption differences of transmitted light is miniscule. The greenish tint is because reflected light is not spectrally neutral. A difference of a few tenths of a percent is very noticeable because only about 1% of light is reflected so it's a big proportion of that. OTOH, a few tenths of 1% variation from the 99% that is transmitted changes things very little.

[trshaner]

My progressive have chromatic aberration apparently.  If I look at lines where large black lines are near white, there will be either a blue or reddish line.  It ah==happens not when I look through the middle of the lens but rather at the top or bottom.  I think it has to do with how much correction there is and also the type of plastic used.

To minimize chromatic aberration a high ABBR value lens needs to be used such as crown glass or CR-39 plastic. A good article here: http://www.starreloaders.com/edhall/abbevalues.html

[Sebastrue]

I have not even tried looking at paper white with them on and off. I recently ran over them in the car and will probably not have that coating added to my next good pair of glasses. I could not tell any improvement in terms of working on the computer all day at work (I'm a doctor so that's all we do anymore).

The tint of the glasses look purplish when looking at the glasses. There is no perceived tint at all when looking through them. But when you compare how the monitor looks with them on verses off there is a distinct warm tint throughout the image.

Bottom line is, I will not add this coating for computer monitor glare to future glasses but I will be checking to see if the standard anti-glare coatings have any effect.

I think this warm effect is totally alright if you don't need to see the colors exactly as they are. Our eyes seem to react better on warmer colors than on contrast bright cold colors, so it's ok. If there are willing people who do not have time to do tests of glasses after purchasing them, I recommend visiting the site giving you the opportunity to try and buy highly-qualitative products in the form of a variety of sunglasses that will not let you down!  I often use layoners.com to buy myself or friends as a gift  sunglasses, because there is a combination of quality and price. For high-end products that will last longer than the 30$ guarantee, this is a drop in the ocean. Sunglasses that I purchased about 8-9 months ago that summer still help me spend leisure time without worrying about the sun.