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The Blinking Eye

Was this QC'd correctly? Confused.

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On 05/10/2019 at 21:39, Colin Woods said:

I can see some banding in the sky top left, but that is probably a product from Alamy converting the photo to a small jpeg for quick previews.

 

I think you're right, based on some tests.

 

Mark

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Posted (edited)
6 hours ago, The Blinking Eye said:

 

Thanks for this explanation. I understand it in concept and it confirms my thinking that one should avoid retouching photos as much as possible. So I looked back at the image in my software program and while I had not adjusted the saturation, I had adjusted the brightness substantially, and did very minor tweaks on the shadows, contrast etc. So even though it was a RAW file, I could see the chunky effects happening with the adjustments. And ironically, this is one of the photos that looks fine without any adjustments at all, so I'll upload it again.

 

It looks like you have figured it out and the mucky sky at the top left (which is clearly visible when downloading the preview image and viewing in Photoshop) is not just due to Alamy artefacts although it may be made worse by whatever processing Alamy does to these files.

 

One thing I would have suggested and I am surprised that nobody else appears to have suggested it would be to upload the final JPEG to Dropbox or the like so as we could have a look at what you actually uploaded. You could even upload the raw file to Dropbox if you want. If that was my image I would probably apply different raw processing to it although it is difficult to say without having the raw file.

 

I use Lightroom (I recall you are using Mac Photos which is more limited but the principles are similar). To get a dark blue sky I would simply darken the blue and increase saturation for blue alone using the HSL controls (this is possible in Photos under Selective Color). Then I would add some noise reduction on the raw image (not add noise in PS as Bill suggested). The blue channel is always the noisiest and prone to blockiness and banding and it is far better to deal with this on the raw image than in PS. In this case I would add a grad filter at an angle over the left side of the image and add further local noise reduction. I don't think Photos has local grad adjustments so you probably won't be able to do this so your noise reduction will have to be applied to the whole image. It is a matter of balancing the noise reduction with the overall sharpness and there are various ways of doing this in Lightroom (or ACR). Finally, you could try downsizing the image which reduces noise and increases overall sharpness (not sure if this would adversely affect the sky but worth a try).

 

To see how noisy the blue channel actually is, I would suggest temporarily converting the raw image to black and white and looking at the sky at 100%. The results can be shocking but noise reduction on the raw file usually works very well.

Edited by MDM

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Posted (edited)
1 hour ago, MDM said:

 

It looks like you have figured it out and the mucky sky at the top left (which is clearly visible when downloading the preview image and viewing in Photoshop) is not just due to Alamy artefacts although it may be made worse by whatever processing Alamy does to these files.

 

One thing I would have suggested and I am surprised that nobody else appears to have suggested it would be to upload the final JPEG to Dropbox or the like so as we could have a look at what you actually uploaded. You could even upload the raw file to Dropbox if you want. If that was my image I would probably apply different raw processing to it although it is difficult to say without having the raw file.

 

I use Lightroom (I recall you are using Mac Photos which is more limited but the principles are similar). To get a dark blue sky I would simply darken the blue and increase saturation for blue alone using the HSL controls (this is possible in Photos under Selective Color). Then I would add some noise reduction on the raw image (not add noise in PS as Bill suggested). The blue channel is always the noisiest and prone to blockiness and banding and it is far better to deal with this on the raw image than in PS. In this case I would add a grad filter at an angle over the left side of the image and add further local noise reduction. I don't think Photos has local grad adjustments so you probably won't be able to do this so your noise reduction will have to be applied to the whole image. It is a matter of balancing the noise reduction with the overall sharpness and there are various ways of doing this in Lightroom (or ACR). Finally, you could try downsizing the image which reduces noise and increases overall sharpness (not sure if this would adversely affect the sky but worth a try).

 

To see how noisy the blue channel actually is, I would suggest temporarily converting the raw image to black and white and looking at the sky at 100%. The results can be shocking but noise reduction on the raw file usually works very well.

 

All good advice, but I'd argue the dominant factor here is Alamy's use of lower quality jpgs to store previews. This is perhaps illustrated when looking at the blue sky in the enlarged preview of the blue sky in TTDWGF (which you can compare versus your original).

 

Mark

Edited by M.Chapman

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8 minutes ago, M.Chapman said:

 

All good advice, but I'd argue the dominant factor here is Alamy's use of lower quality jpgs to store previews. This is perhaps illustrated when looking at the blue sky in the enlarged preview of the blue sky in TTDWGF (which you can compare versus your original).

 

Mark

 

You are most probably right Mark. I will let you know.

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Eek. I've got it too. It's most obvious in the few seconds before LR renders its 1:1 preview- a similar sort of effect to the Alamy views, then it just shows as noise in the blue.

I may try a bit of MDM's NR in an import preset.

These images are getting through QC (and licensing) so evidently not too much of a problem for buyers, but one still wants to do one's best.

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Mystery solved, everybody. Thanks for all your input. I uploaded the photo again, exported from the RAW file, without any corrections. It's clearly just the way it shows up on Alamy. The banding on the two shots looks different but both bad. For the top one, I did slight brightness adjustments.  The bottom one, none.

 

Photo #1 that launched this debate:La iglesia de Santa Ana, Church of Santa Ana, barrio de Peralvillo, Cuauhtémoc. Papel picado (cut paper flags) and bell tower with cross. Mexico City. Stock Photo

 

 

 

 

 

Photo #2 that got QC'd yesterday

 

La iglesia de Santa Ana, Church of Santa Ana, el barrio de Perslvillo. La Delegación Cuauhtémoc. Papel picado (cut paper flags). Mexico City, Mexico. Stock Photo

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Personally, I never worry much about a little banding and/or "chunkiness" in dark blue skies. Apparently QC doesn't either. Sometimes it's unavoidable.

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10 hours ago, John Mitchell said:

Personally, I never worry much about a little banding and/or "chunkiness" in dark blue skies. Apparently QC doesn't either. Sometimes it's unavoidable.

QC don’t look at the over-compressed jpgs that Alamy are using to display our image thumbnails and previews. They inspect the original jpgs we upload (which they will fail if they show obvious banding). If you want to see what’s going on take an image with nice (no banding visible) blue sky with  gradient and save at a range of jpg quality levels. My guess is Alamy are using level 7 or similar. 

 

Mark

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2 hours ago, M.Chapman said:

My guess is Alamy are using level 7 or similar. 

 

Mark

 

I've always been meaning look at the Alamy listed file size for one of my images, then save my original at progressively lower resolutions until the file size matches to determine the compression they use for sales. I would now but and busy editing on a train.

Edited by sb photos

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16 hours ago, sb photos said:

 

I've always been meaning look at the Alamy listed file size for one of my images, then save my original at progressively lower resolutions until the file size matches to determine the compression they use for sales. I would now but and busy editing on a train.

 

When I recently purchased a couple of my own images from Alamy (to check if they really were converting AdobeRGB to sRGB) they were supplied as jpgs with level 12 quality. The images I uploaded were at Level 10. The previews I downloaded were also at quality level 12.

 

But, I believe the thumbnails and preview images Alamy display on screen are at a significantly lower quality level (I guess around 7).

 

To see the effect of differing levels of jpg compression on a blue sky took a 1000 x 100 pixel crop from the blue sky in one of my RAW files and saved at jpg levels 0 to 12. Those 13 files can be found here. Stepping through them shows the progressive appearance of banding as the jpg level level is decreased.

 

I also created a composite image by opening the 13 files in PS and tiling them vertically and taking a screenshot which is below. (Although it's better to view the file directly as the rendering in the forum posting isn't as clear (on my system anyway). The composite file is also in the gallery.

 

Level-00-12-Composite.png

  

Note: I tried similar tests with red and green gradients and saw similar progressive increases in banding. This suggests it's not really a "blue" issue, although that's probably were it's noticed most often because of the frequent occurrence of blue skies with subtle gradients in photos.

 

Mark

Edited by M.Chapman
Updated to include better quality screenshot.
  • Upvote 2

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8 minutes ago, M.Chapman said:

 

When I recently purchased a couple of my own images from Alamy (to check if they really were converting AdobeRGB to sRGB) they were supplied as jpgs with level 12 quality. The images I uploaded were at Level 10. The previews I downloaded were also at quality level 12.

 

But, I believe the thumbnails and preview images Alamy display on screen are at a significantly lower quality level (I guess around 7).

 

To see the effect of differing levels of jpg compression on a blue sky took a 1000 x 100 pixel crop from the blue sky in one of my RAW files and saved at jpg levels 0 to 12. Those 13 files can be found here. Stepping through them shows the progressive appearance of banding as the jpg level level is decreased.

 

I also created a composite image by opening the 13 files in PS and tiling them vertically and taking a screenshot which is below. (Although it's better to view the file directly as the rendering in the forum posting isn't as clear (on my system) anyway. The composite file is also in the gallery.

 

Levels-00-12-composite.jpg

  

Note: I tried similar tests with red and green gradients and saw similar progressive increases in banding. This suggests it's not really a "blue" issue, although that's probably were it's noticed most often because of the frequent occurrence of blue skies with subtle gradients in photos.

 

Mark

 

I can see vertical lines in the edges of the blue close to the black. Do you know why that might be?

 

Allan

 

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28 minutes ago, Allan Bell said:

 

I can see vertical lines in the edges of the blue close to the black. Do you know why that might be?

 

Allan

 


Thanks - Must be an artefact from jpg compression of the screenshot and the rendering in the forum posting. I've just updated my posting to use a PNG version of the composite which seems to avoid (reduce) the problem with the edges and makes the banding clearer.

 

Level-00-12-Composite.png

 

It's still best to look at the individual jpgs in the gallery here. Suggest downloading them and then stepping through them at 100% size in whatever image browser you use.

 

Mark

Edited by M.Chapman

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I wonder how good most customers' monitors are. If they are anything like mine, then there is nothing to worry about. I can't even see the problem(s) with the first image that Blinking Eye posted. Oh dear, it might be time to spend more money that I don't have. 🙄

Edited by John Mitchell

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5 hours ago, John Mitchell said:

I wonder how good most customers' monitors are. If they are anything like mine, then there is nothing to worry about. I can't even see the problem(s) with the first image that Blinking Eye posted. Oh dear, it might be time to spend more money that I don't have. 🙄

 

Didn't you mention something about having cataract surgery planned or am I mistaken? Visual acuity is greatly affected by cataracts so perhaps you don't need a new monitor, just new lenses. In any case the easiest way to see the blobby sky under discussion is to save the preview image and view it at 1:1 or higher in Photoshop or other image editor, perhaps modifying brightness and contrast.

 

On 07/10/2019 at 10:58, M.Chapman said:

 

All good advice, but I'd argue the dominant factor here is Alamy's use of lower quality jpgs to store previews. This is perhaps illustrated when looking at the blue sky in the enlarged preview of the blue sky in TTDWGF (which you can compare versus your original).

 

Mark

 

 

Yes you are correct - the downsizing introduces banding and blobbiness, more evident in images taken with the ony RX100M than those taken with a full frame Nikon at the same time and at same ISO - not terribly surprising really. 

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1 hour ago, MDM said:

 

Didn't you mention something about having cataract surgery planned or am I mistaken? Visual acuity is greatly affected by cataracts so perhaps you don't need a new monitor, just new lenses. In any case the easiest way to see the blobby sky under discussion is to save the preview image and view it at 1:1 or higher in Photoshop or other image editor, perhaps modifying brightness and contrast.

 

 

Yes, it could have something to do with eyesight. However, I just looked at the preview image as it is, and it appears fine on my monitor. If I downloaded the comp and viewed it at 1:1 as you suggest, I would expect to see blobby sky and other compression problems. My guess is that most clients wouldn't bother to do this, though.

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2 hours ago, MDM said:

 

Didn't you mention something about having cataract surgery planned or am I mistaken? Visual acuity is greatly affected by cataracts so perhaps you don't need a new monitor, just new lenses. In any case the easiest way to see the blobby sky under discussion is to save the preview image and view it at 1:1 or higher in Photoshop or other image editor, perhaps modifying brightness and contrast.

 

 

 

Yes you are correct - the downsizing introduces banding and blobbiness, more evident in images taken with the ony RX100M than those taken with a full frame Nikon at the same time and at same ISO - not terribly surprising really. 

 

Mine were shot with a Sony a6000.

 

And I absolutely LOVE how invested you guys are in this topic. 😄

 

But this is why I will always prefer the fine beauty of analog emulsion and grain.

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Interesting to see the 'bar graph' comparisons, though it is also worth doing one's own from time to time by stacking images or sections of images as layers in Photoshop saved at different jpeg compressions in order to see the way jpeg compression degrades the image. Presumably ImageMagick is used by Alamy rather than Photoshop but it's likely to have broadly similar results. What struck me on this particular example is how there is quite an obvious band on Level 07 about 2/3 of the way up which isn't there on examples to the right, unsurprisingly, but isn't as obvious on Levels 05 & 06 to the left either. There is going to be some randomness in how these blocky artefacts are produced after jpeg compression.

Edited by Harry Harrison

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16 hours ago, John Mitchell said:

 

Yes, it could have something to do with eyesight. However, I just looked at the preview image as it is, and it appears fine on my monitor. If I downloaded the comp and viewed it at 1:1 as you suggest, I would expect to see blobby sky and other compression problems. My guess is that most clients wouldn't bother to do this, though.

 

Sure. Much of this thread is academic really but interesting. In practice it doesn't really matter about banding in the Alamy preview image unless it puts a potential client off licensing an image.

 

16 hours ago, The Blinking Eye said:

 

Mine were shot with a Sony a6000.

 

And I absolutely LOVE how invested you guys are in this topic. 😄

 

But this is why I will always prefer the fine beauty of analog emulsion and grain.

 

I find all this stuff interesting myself and generally worth knowing about. As for the fine beauty of analog emulsion and grain, then I think that is great as long as you are using traditional chemical printing to view the images but it suffers massively in the digitisation unless using a very, very high end scanner. And then there is the chemical mess. Uugh. A little nostalgia is fine but I am more than happy with digital imaging including printing - call inkjet giclée to make it sound posh and exclusive but I would never want to go back to wet printing. 😀

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19 hours ago, The Blinking Eye said:

But this is why I will always prefer the fine beauty of analog emulsion and grain.

 

I'm with you there, but as MDM says I was never really that happy about the chemistry, particularly the replenished colour chemistry that I was getting rid of. That said there's a pretty huge environmental cost to inkjet printers, my local tip is full of them, either because they have blocked up or more likely the drivers have become unobtainable so perfectly good printers are junked. High end printers are no better sadly, they very quickly become uneconomical to repair:

 

https://www.youtube.com/watch?v=Bf6kOEtgQqE

 

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On 20/10/2019 at 10:56, MDM said:

 

Sure. Much of this thread is academic really but interesting. In practice it doesn't really matter about banding in the Alamy preview image unless it puts a potential client off licensing an image.

 

 

I find all this stuff interesting myself and generally worth knowing about. As for the fine beauty of analog emulsion and grain, then I think that is great as long as you are using traditional chemical printing to view the images but it suffers massively in the digitisation unless using a very, very high end scanner. And then there is the chemical mess. Uugh. A little nostalgia is fine but I am more than happy with digital imaging including printing - call inkjet giclée to make it sound posh and exclusive but I would never want to go back to wet printing. 😀

 

It's nice to hear that perspective. I do like being able to manipulate the images with a click of a mouse, but I feel like I can always see the difference, and I love and miss that grainy look. Especially with projected film on the big screen.

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On 20/10/2019 at 21:52, Harry Harrison said:

 

I'm with you there, but as MDM says I was never really that happy about the chemistry, particularly the replenished colour chemistry that I was getting rid of. That said there's a pretty huge environmental cost to inkjet printers, my local tip is full of them, either because they have blocked up or more likely the drivers have become unobtainable so perfectly good printers are junked. High end printers are no better sadly, they very quickly become uneconomical to repair:

 

https://www.youtube.com/watch?v=Bf6kOEtgQqE

 

 

🤣🤣 Great video. I've got the Epson SC-P600 which is A3+  max and purchase by me in April 2015 shortly after it hit the market so not high end but a fantastic prosumer printer.  It has never had a clogged print head - I use it on the Photo Black setting and haven't changed to the Matte Black setting in ages - so either mine is very special or the Ultrachrome inks are very good in that respect.

 

My previous Canon 9500 was always getting clogged and used masses of ink in the cleaning as did my much older Epson 1290. In fact my original Epson 1290 developed a serious problem just as the one year guarantee ran out but Epson sent a techie guy out to my house and after checking it out he gave me a brand new printer which lasted about 5 years. I don't know if that would happen nowadays. 

 

I think it is very difficult for most of us to compare printer makes as we don't generally have two of the same vintage to compare. No doubt Canon have improved on the 9500 which I bought in 2008. The Epson SC-P600 came out in 2015 and is way better but such a comparison is unfair really. 

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36 minutes ago, The Blinking Eye said:

 

It's nice to hear that perspective. I do like being able to manipulate the images with a click of a mouse, but I feel like I can always see the difference, and I love and miss that grainy look. Especially with projected film on the big screen.

 

Well you can try to simulate film with digital and project that or simply start shooting film again. I reckon you can pick up some second hand kit cheaply. I stlll have a Nikon film camera but it has not been used in a long long time and maybe never will be. I kept it because the price I was offered was so bad it was not worth trading in. 

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6 hours ago, The Blinking Eye said:

 

It's nice to hear that perspective. I do like being able to manipulate the images with a click of a mouse, but I feel like I can always see the difference, and I love and miss that grainy look. Especially with projected film on the big screen.

 

I've never missed film grain, having always tried to minimise it. At times it couldn't be avoided, and it was always better to have a sharp grainy image than one with less grain but not stopping motion and out of focus, so did often uprate HP5 to iso 1600. For static subjects I used 6x6, then 6x7, then 4x5 cut film trying to achieve grain free images.

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7 hours ago, MDM said:

 

I think it is very difficult for most of us to compare printer makes as we don't generally have two of the same vintage to compare.

About 10 years ago I innocently thought that I would buy a s/h commercial grade printer, an Epson 4000, as it would be better made, over-engineered for my purposes and the cost of the ink in the large cartridges was far less per litre than in the prosumer models. All that was true but I had a lot of trouble with blocked nozzles and it could easily cost £50 in ink just to clear them. False economy! A friend still has the A3+ 2100 prosumer version with the exact same print head and ink set, never has a problem. There’s a lesson there.

 

I don’t blame the printer, in fact I now know that the fault is most likely down to the ‘capping station’ where the head parks itself, the rubber seal to the atmosphere goes and the head dries out. I should have replaced it, still could actually but I have its successor, the 4880, now and that has been faultless.

 

Incidentally since we’re talking about digital B&W, the single ‘Light black’ grey of the 4000 meant it was never very good for B&W prints, the 4880 has two greys, adding a ‘Light Light Black’ and is excellent, particularly if using the Epson Advanced Black & White printing mode (ABW). The only downside to the 4880, which is true of a lot of printers, is that switching from gloss Photo Black ink to Matte Black is fairly convoluted and again wastes about 50 quid’s worth of ink as the tubes and head are flushed so I don’t tend to do it.

 

Edit:

Oops, we're not talking about digital B&W here, that's the other thread. Sorry!

Edited by Harry Harrison

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