[Tig] Macular degeneration, etc. caused by the blue-violet light of tablets, smartphones

Richard Kirk richard at filmlight.ltd.uk
Sun Apr 20 09:10:10 BST 2014


On 20 Apr 2014, at 01:08, tig-request at colorist.org wrote:

> I used the prescribed Crizal UV blocking lenses and was able to work pain free.  My optometrist said they were equivalent to 25 SPF for your eyes.  There is however a slight color shift when wearing them and that brings up a very tricky subject.  Can one claim to be providing color critical viewing when using protective lenses that induce a color shift?
> 
> My response would be no, yet a qualified no.  If you are knowingly introducing bias, however minimal, you are deviating from our core principles.

Hi, Dave.

I have been trying to find the spectral qualities of your glass lenses, in order to try and estimate the shift they may give to your vision.

I think you are morally correct in wanting to put as little between your eyes and the image; but I suspect there is little practical difference. I have been trying to find the spectral qualities of your glass lenses, in order to try and estimate the shift they may give to your vision, but no joy. Contact lenses have a blueish dye to them, and no-one seems to complain about that.

You could increase the red - and perhaps green too - of your display to correct for this. However, our eyes are very quick to adapt to the ambient white. If the slight blue cast covers the whole image and you are in a darkened room, then I expect they have already done the job.

>  I highly respect the science behind accurate viewing environments.  I have also, however, graded in many variations of that theme.  Grey rooms, biege rooms, black and white rooms, PAL rooms, PAL monitors in NTSC facilities and vice versa.  Flickering 24p CRTs, flicker free CRTs, LCDs, Plasmas, projectors and even the occasional sunlight leak masked to a degree with curtains.  Through all of that variation I usually rely on two things.  My feel for imagery and the scopes.  For therein lies the truth.

Well, speaking as one of these so-called colour scientists, I can say that a lot of this is over-rated and  not nearly as scientific as we would like. I was very sceptical of the UV correction, but the new glasses seem to work, so I was quite wrong there. There is some variation in healthy eyes - the red and green spectral sensitivities vary a bit; the ratio between red and green cell counts vary a lot; the distribution of macular dye varies a lot, and the yellowness of the lens varies with age. We are not born with a sense of D65, but we train our eyes to see what is there, and back it up with scopes and measurements. I think what makes you a grader is your training and experience, and not the absolute calibration of your eyes. If you wear your new glasses for all your grading work, and don't take them on and off, then I expect you are as good as you ever were.

All the best.

Richard Kirk




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