Expert's Presentation on computer screens and image viewing

[Manfred M]

The link here is a recent presentation made by Dr Bob Ito, an emeritus professor of electrical and computer engineering at the University of British Columbia in Vancouver, Canada. He is also the Director of Photographic Imaging at the Canadian Association for Photographic Art (CAPA).

The presentation was delivered at a recent CAPA workshop for training judges. While the context is primarily viewing images while judging competitions, the points he makes are usually transferable to what we need to look for when choosing and using a computer screen.

The presentation, of around 15 slides, has been converted to a pdf that can be downloaded for viewing.


https://www.dropbox.com/s/ckd9wpjeyy...0CAPA.pdf?dl=0

[xpatUSA]

Thanks for the link, Manfred. While I dare not comment on anything related to act of judging, I would mention a couple of issues.

Under tonal accuracy, the definition of middle-gray seems a little high. While many people think that middle-gray is 127 or 128 out of 255, the technical definition is 117 or 118.

Under color gamut, he says that the CIE horseshoe depicts the gamut of a camera sensor - not true. Camera sensors, even with the CFA, are often wider.

Under color gamut - is ProPhoto really the default color space in LR, or is it some Adobe version thereof? (bearing in mind that ProPhoto's white reference is D50 and it's gamma is 1.8 ...)

I have no comment on the "Common Misconceptions" other than some appear to be rather trivial ...

[DanK]

From what little I have read, Melissa is a hybrid of the ProPhoto color space and an sRGB gamma curve.


Sent from my iPad using Tapatalk

[xpatUSA]

From what little I have read, Melissa is a hybrid of the ProPhoto color space and an sRGB gamma curve ...

... and a D65 white reference - therefore it is not ProPhoto RGB (formerly known as Kodak ROMM but unchanged therefrom).

[DanK]

Still, the presentation has some good advice for those who don't know it.

BTW, I'm embarrassed to say that when I recalibrated my NEC monitor a few days ago, I used the ambient light measurement capabilities of the i1 pro for the first time in many years. I found that I was badly underestimating the brightness of my editing room.

On the plus side, it liked the Soraa bulbs I splurged on for that room. It measured them at precisely 3000K.

[Manfred M]

Thanks for the link, Manfred. While I dare not comment on anything related to act of judging, I would mention a couple of issues.

Under tonal accuracy, the definition of middle-gray seems a little high. While many people think that middle-gray is 127 or 128 out of 255, the technical definition is 117 or 118.

Under color gamut, he says that the CIE horseshoe depicts the gamut of a camera sensor - not true. Camera sensors, even with the CFA, are often wider.

Under color gamut - is ProPhoto really the default color space in LR, or is it some Adobe version thereof? (bearing in mind that ProPhoto's white reference is D50 and it's gamma is 1.8 ...)

I have no comment on the "Common Misconceptions" other than some appear to be rather trivial ...

Ted - this is why I identified the audience. What Ito has done is made it understandable to a crowd that is mostly non-technical.

It seems he shares my view that the presentation should be geared to the audience, even if it can be argued that it is NOT technically 100% correct. It is far more important that the audience understands the important part of the message, in my experience.

I have seen his analysis on the difference between sRGB the Rec. 709 standard (typically used in commercial video projectors) argued to a standards approval committee; he knows this stuff but also knows when he is going over someone's head, so sticks with explaining things in a way that his audience will grasp without them feeling stupid and turning off.

Many years ago, one of my final year optional courses when I was studying engineering was a technical writing / presentation course. The first thing we were told was to understand who the audience was and tailor both our technical content and the level of language (grammar, sentence structure and word choice) to the audience. We were taught that making the reader feel dumb or otherwise losing the connection with them was generally worse than not being 100% technically correct, as the reader would either stop reading or develop a negative view of the author. Engaging the reader and getting the appropriate level of knowledge across was what we were trying to accomplish.

[xpatUSA]

Ted - this is why I identified the audience. What Ito has done is made it understandable to a crowd that is mostly non-technical.

It seems he shares my view that the presentation should be geared to the audience, even if it can be argued that it is NOT technically 100% correct. It is far more important that the audience understands the important part of the message, in my experience.

I stand corrected. I suppose too that it really doesn't matter that his statement "100 nits = 1/30 sec @ f:6.3@ISO 200" is off by 25% - because his audience probably had no idea what a "nit" is anyway ...

[Manfred M]

I stand corrected. I suppose too that it really doesn't matter that his statement "100 nits = 1/30 sec @ f:6.3@ISO 200" is off by 25% - because his audience probably had no idea what a "nit" is anyway ...

You still don't get it...

[DanK]

As long as we have the prompt of this expert's advice, I am going to call one standard piece of advice into question.

Last night I participated via Webex in an electronic image competition. I viewed the competition on my NEC color-critical monitor, set to 110 cd/m^2. I made the room lighting dim, roughly at the level recommended for editing.

One of my entries was this image, which I have posted before:



I didn't win. The judge, who I thought was very good, had two criticisms. I ended the session expecting to re-edit the photo. Now I have my doubts.

The judge's first criticism was relevant to this thread. He said that the orange-red tree on the far left and its reflection were too bright and intense and pulled the eye to the edge. Looking at the image on screen, I agreed with him, and I wondered how I hadn't seen this before, as I have printed this numerous times and have re-edited it at least once.

After the session was over, I went downstairs to look at a 13 x 19 print of this image hanging on a white wall. Lo and behold, the red was much less intense, just as I remembered it.

So, just now, I called up the image on the same monitor again, but this time with normal indirect daylight illuminating the room. Under these circumstances, the image on the screen is very close to what I see in the print. Tonight, once it is dark enough, I'll replicate the conditions I had last night during the competition, but cutting out the intervening steps (the judge's computer, the webex software, and the transmission) to see if I get the same thing. But in the meantime, this makes me question the standard advice to edit in dark ambient light.

The second criticism was interesting for another reason. It also had to do with that one tree. He wanted me to subdue the color in that tree and its reflection, while increasing colors to the right, closer to the center. That too is standard advice, and it's similar to advice I have given other people. If the reds were as intense in the print as on screen in the dark, I would be inclined to agree with him. But looking at both the print and the image on screen now, I think I disagree. I think the tree serves as an anchor. The balance is between a small area on the left that is quite intense (I think of this as high weight) and a much larger area on the right that is lower in intensity (weight).

Any reactions to this?

[Manfred M]

Dan - your points are valid and I think the issue is how we define "dark".

The CAPA recommendation is that light level in the work area should be below 70 lux. My editing room, at the work station is set at around 40 lux. Frankly, that is hardly dark, once my eyes adjust, but if I come in from outside, the room looks quite dimly lit. So far as I recall, the screen is currently set to 80 cd/square metre, and I generally don't get a lot of negative comments on the colour depth and contrast.

I started scoring very well in competitions when I worked to "calm" my images, i.e. burn down the bright area and dodge the darker ones. If this were my image, I would not only calm down the red tree on the left and its reflection in the water, I would do the same with the with the platform the people are on as it adds to pulling the viewer's eyes to the left edge of the image.

I might also take the bush at the tree down a touch and would definitely brighten all those dark bushes along the water's edge just a touch as well (including the relevant reflections).

[Round Tuit]

As long as we have the prompt of this expert's advice, I am going to call one standard piece of advice into question.

Last night I participated via Webex in an electronic image competition. I viewed the competition on my NEC color-critical monitor, set to 110 cd/m^2. I made the room lighting dim, roughly at the level recommended for editing.

One of my entries was this image, which I have posted before:


I didn't win. The judge, who I thought was very good, had two criticisms. I ended the session expecting to re-edit the photo. Now I have my doubts.

The judge's first criticism was relevant to this thread. He said that the orange-red tree on the far left and its reflection were too bright and intense and pulled the eye to the edge. Looking at the image on screen, I agreed with him, and I wondered how I hadn't seen this before, as I have printed this numerous times and have re-edited it at least once.

After the session was over, I went downstairs to look at a 13 x 19 print of this image hanging on a white wall. Lo and behold, the red was much less intense, just as I remembered it.

So, just now, I called up the image on the same monitor again, but this time with normal indirect daylight illuminating the room. Under these circumstances, the image on the screen is very close to what I see in the print. Tonight, once it is dark enough, I'll replicate the conditions I had last night during the competition, but cutting out the intervening steps (the judge's computer, the webex software, and the transmission) to see if I get the same thing. But in the meantime, this makes me question the standard advice to edit in dark ambient light.

The second criticism was interesting for another reason. It also had to do with that one tree. He wanted me to subdue the color in that tree and its reflection, while increasing colors to the right, closer to the center. That too is standard advice, and it's similar to advice I have given other people. If the reds were as intense in the print as on screen in the dark, I would be inclined to agree with him. But looking at both the print and the image on screen now, I think I disagree. I think the tree serves as an anchor. The balance is between a small area on the left that is quite intense (I think of this as high weight) and a much larger area on the right that is lower in intensity (weight).

Any reactions to this?

Dan,
I think that the answer to your first question is that you should edit in conditions as close as possible to the intended viewing conditions and, if you intend to print, you need to prints proofs and adjust your editing accordingly.
The same advice applies to the second criticism. Adjust the editing to the viewing conditions. As an aside, if I were to attempt to balance the left tree, I would look at slightly increasing the intensity of the far right reddish tree.
HTH

[xpatUSA]

You still don't get it...

Good grief, I was being deliberately obtuse, Manfred - hence the winking emoticon.

[xpatUSA]

As long as we have the prompt of this expert's advice, I am going to call one standard piece of advice into question.

One of my entries was this image, which I have posted before:



I didn't win. The judge, who I thought was very good, had two criticisms. I ended the session expecting to re-edit the photo. Now I have my doubts.

The judge's first criticism was relevant to this thread. He said that the orange-red tree on the far left and its reflection were too bright and intense and pulled the eye to the edge. Looking at the image on screen, I agreed with him, and I wondered how I hadn't seen this before, as I have printed this numerous times and have re-edited it at least once.

After the session was over, I went downstairs to look at a 13 x 19 print of this image hanging on a white wall. Lo and behold, the red was much less intense, just as I remembered it.

The second criticism was interesting for another reason. It also had to do with that one tree. He wanted me to subdue the color in that tree and its reflection, while increasing colors to the right, closer to the center. That too is standard advice, and it's similar to advice I have given other people. If the reds were as intense in the print as on screen in the dark, I would be inclined to agree with him. But looking at both the print and the image on screen now, I think I disagree. I think the tree serves as an anchor. The balance is between a small area on the left that is quite intense (I think of this as high weight) and a much larger area on the right that is lower in intensity (weight).

Any reactions to this?

Setting the matter of monitor lighting to one side, Dan, I see your post as two separate images and therein might lie the difficulty of balancing the whole admittedly spectacular scene.

At left, I see a Monet-esque scene with an artifact up against nature - a bit like his bridge in the garden:



Pardon the Monet-processing and the inappropriate A/R. I did turn down the reds, upped the green a bit, lowered the saturation and added a minimum of oil-paint effect. Upsized with Mitchell.

My background is "about mid-gray".

At right, a riotous scene of fall colors and reflections - subjects in their own right:



Pardon the cranked-up saturation and added micro-contrast, point being that you couldn't have done that to the whole scene. Again, the A/R is inappropriate. Upsized with Lanczos2 (sharper) but still ended up somewhat painterly, almost pointillistic.

That was my main reaction ... two scenes in one.

[DanK]

Thanks for the comments. This one has been a real puzzle for me. I initially wasn't all that pleased with it, but it was better received than almost any of my prints. It's one that I have on display in a gallery, and one of the first people who saw it (not there) said he wanted to buy the largest size I can print. That had never happened to me before, and it has never happened since. Still, I am unsure about it.

I don't think splitting it works. The basic logic of the composition is either this:



or this:



That is also why I am reluctant to done down the trees on the left or the blocks; that area is supposed to have a lot of weight. I'm more sympathetic to the idea of boosting one or more of the red trees toward the right, as I have had the thought that the picture tapers off too quickly when moving to the right.

In any case, being stuck here for the indefinite future, I will have plenty of time to try new edits,and your suggestions will be helpful in that.

[Manfred M]

Dan - I spent a few minutes doing what I suggested in #10.

[DanK]

Manfred,

Thanks. I loaded these both into photoshop and did a difference blend. It seems clear that on the right side, you dodged. However, it wasn't clear to me what you did on the left. The difference blend makes it look like a desaturation of the reds and blues, but I see a shift in hue in the reds as well. Can you clarify?

I think I am persuaded about the dodging. I had been thinking that that area was too dark. Not so sure about the changes on the left.

thanks again

Dan

[Manfred M]

Setting the matter of monitor lighting to one side, Dan, I see your post as two separate images and therein might lie the difficulty of balancing the whole admittedly spectacular scene.

At left, I see a Monet-esque scene with an artifact up against nature - a bit like his bridge in the garden:



Pardon the Monet-processing and the inappropriate A/R. I did turn down the reds, upped the green a bit, lowered the saturation and added a minimum of oil-paint effect. Upsized with Mitchell.

My background is "about mid-gray".

At right, a riotous scene of fall colors and reflections - subjects in their own right:



Pardon the cranked-up saturation and added micro-contrast, point being that you couldn't have done that to the whole scene. Again, the A/R is inappropriate. Upsized with Lanczos2 (sharper) but still ended up somewhat painterly, almost pointillistic.

That was my main reaction ... two scenes in one.

Ted - I'm fairly certain that Monet did not use any global adjustments in his work. I'm pretty sure, just like Ansel Adams (while sticking with landscape photographers), most of the work dealt with very deliberate actions to work with highly localized areas to get the impact that he was looking for.

[Manfred M]

Dan - PM me your email address and I send a you a DropBox link with my retouches as a PSD with all my working layers.

When working in an RGB colour space most of my local work is limited to increasing and decreasing the brightness and local desaturation of specific colour channels. That's really all I did on the left hand side.

[xpatUSA]

Ted - I'm fairly certain that Monet did not use any global adjustments in his work. I'm pretty sure, just like Ansel Adams (while sticking with landscape photographers), most of the work dealt with very deliberate actions to work with highly localized areas to get the impact that he was looking for.

I fold ...

[DanK]

I just re-edited the image in the light of the discussion here. I brightened and slightly intensified the colored areas on the right but left the center of the right part as it was (after trying lightening it a bit). I darkened the left a bit and desaturated the red trees on the left very slightly.

I think this is better, although I think it still would not have satisfied the judge.

I'll post the original and the new together to make the subtle differences easy to see.

If these images disappear, it means that I have moved the new one to my public galleries on smugmug, which will break the links.

Original:



modified: