Was this QC'd correctly? Confused.

[The Blinking Eye]

This photo of mine looks bad on Alamy. But why? I edited it slightly as a RAW file and when I examine it at 100% it looks perfectly fine. But on Alamy, the sky looks chunky. I like the photo and want to use it. I freaked out and deleted it, but I guess it takes a while for it to disappear. Not sure what's going on, but it passed QC.

 

https://www.alamy.com/la-iglesia-de-santa-ana-church-of-santa-ana-el-barrio-de-perslvillo-la-delegacin-cuauhtmoc-papel-picado-cut-paper-flags-mexico-city-mexico-image273775823.html?pv=1&stamp=2&imageid=AF3A8287-F6CD-423D-A02A-EB4E1B0CB1D0&p=819131&n=0&orientation=0&pn=1&searchtype=12&IsFromSearch=1&srch=foo%3dbar%26st%3d12%26pn%3d1%26ps%3d100%26sortby%3d2%26resultview%3dsortbyPopular%26npgs%3d0%26qt%3d%26qt_raw%3d%26lic%3d3%26mr%3d0%26pr%3d0%26ot%3d0%26creative%3d%26ag%3d0%26hc%3d0%26pc%3d%26blackwhite%3d%26cutout%3d%26tbar%3d0%26et%3d0x000000000000000000000%26vp%3d0%26loc%3d0%26imgt%3d0%26dtfr%3d%26dtto%3d%26size%3d0xFF%26archive%3d1%26groupid%3d%26pseudoid%3d%26a%3d%26cdid%3d%26cdsrt%3d%26name%3dKristin%20Cato%26qn%3d%26apalib%3d%26apalic%3d%26lightbox%3d%26gname%3d%26gtype%3d%26xstx%3d0%26simid%3d%26saveQry%3d%26editorial%3d1%26nu%3d%26t%3d%26edoptin%3d%26customgeoip%3dUS%26cap%3d1%26cid%3d6FTPULFS5B6X2AMJYWJ9AK35EVUKYLCKWC55R93RDFBGMG8XADXYZB6NJG9DTDZT%26vd%3d0%26lb%3d%26fi%3d2%26edrf%3d%26ispremium%3d1%26flip%3d0%26pl%3d

 

[Colin Woods]

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. If it looks fine to you at 100% and QC passed it, then its probably fine.

[John Morrison]

I can't see any issues with the sky (apart from all those 'a's!)...

 

 

[Mr Standfast]

Hello Kristen,

Yes, you have some artefacts in the sky. The QC help page has a similar example.

As for QC'd correctly, well they only do a spot check, so may not have looked at every picture in your submission.

We've all let one through at one time or another. Any one who says they have not just has'nt found it yet.

[Mr Standfast]

Ok I'm going to look on another screen....

[The Blinking Eye]

I'm getting conflicting feedback. Some see it, some don't. Colin says it's from Alamy conversion (but would a customer buy such a thing?). Mr. Standfast says it's on the original, but I don't see it at all on the original.

 

I HAVE noticed dirt specks on other QC'd photos. Trying to be eagle-eyed as possible now, but it's easy to miss them.

 

I have two screens -- a Mac and a Dell, and I see it on both. Looks really bad to me.

[The Blinking Eye]

7 minutes ago, John Morrison said:

I can't see any issues with the sky (apart from all those 'a's!)...

 

 

 

This is very odd.

[John Morrison]

I can't see any issue at this resolution (but then I'm normally inspecting skies - mostly for dust-spots - at 100%)...

[The Blinking Eye]

1 minute ago, John Morrison said:

I can't see any issue at this resolution (but then I'm normally inspecting skies - mostly for dust-spots - at 100%)...

 

I think you would see it. It's looks very obvious. Others see it!  So weird.

[Mr Standfast]

Ok...The Picture as posted is not so pronounced on my main PC, I may not have seen it if I had'nt been directed to it. On my inexpensive tablet it's clear. I'm confused.

 

I've downloaded the preview and looked at it again in PS, again there is something in the top left of the sky, but not the same as I saw on the tablet.

 

I like the picture, it's bold and worth saving. If you have the raw, a little bit of blur to the top left and try again.

 

I'm sorry I cannot offer any more clarity.

 

G'night

 

 

 

 

[The Blinking Eye]

3 minutes ago, Mr Standfast said:

Ok...The Picture as posted is not so pronounced on my main PC, I may not have seen it if I had'nt been directed to it. On my inexpensive tablet it's clear. I'm confused.

 

I've downloaded the preview and looked at it again in PS, again there is something in the top left of the sky, but not the same as I saw on the tablet.

 

I like the picture, it's bold and worth saving. If you have the raw, a little bit of blur to the top left and try again.

 

I'm sorry I cannot offer any more clarity.

 

G'night

 

 

 

 

 

Thanks!

[AM Chang]

I think there is not much to worry about.

Most of the pictures with blue sky I saw on the Alamy website, including mine, depending on the blue tone, they look "chunky" in the Alamy preview. At least on my laptop screen.

 

andre

Edited October 5, 2019 by AM Chang

[M.Chapman]

I can see some blocking/banding/posterisation in your image on Alamy.  This is the sort of effect that's often caused by altering contrast/levels/highlights whilst working in 8 bit instead of 16 bit mode in PS. I've just looked at one of my images on Alamy website (F5KR0T) and I see the same problem in the blue sky. The jpg I uploaded is fine.

 

It's almost certainly something to do with the way Alamy is displaying our images on their website. It's a shame that they don't look their best . Hopefully the customer's downloads are OK

 

Mark

 

 

Edited October 5, 2019 by M.Chapman

[Mr Standfast]

AM and Mark,

Thank you.

James

[Joseph Clemson]

I've no comment on the photo but just to address an assumption in your topic titile and initial post. You say that it passed QC. Unless it was the only image in that particular submission, it was not necessarily QC'd by the Alamy team, who only check a small proportion of our submissions.  Thisis why it's so important that each contributor has a thorough QC check of their own for every picture in every submission - Alamy are only a safety net to catch us if our standards slip. 

 

I'm sure the The Blinking Eye is aware and  understands this, but some who come from a microstock background sail on thinking that Alamy QC will catch any sub-standard images if they simply upload as much and as fast as they can. This is not the case and I feel the need to point it out when the actual nature of how Alamy QC works is unwittingly presented inaccurately.

[The Blinking Eye]

Thanks everyone. Still feel like I'm muddling through this process.

[The Blinking Eye]

ok, on closer inspection, I AM seeing that banding on other photos, just not as obviously, so I think it's the Alamy preview.

[jodyko]

2 hours ago, The Blinking Eye said:

I freaked out and deleted it, but I guess it takes a while for it to disappear.

I don't think they ever disappear. I did something similar early on and the photo is still in my image manager though clearly marked as deleted.

 

2 hours ago, The Blinking Eye said:

when I examine it at 100% it looks perfectly fine.

Wouldn't worry about it personally but you might reinspect before re-submitting to put yourself at ease. I've noticed blockiness in the skies on the previews, some from very experienced contributors. On my monitor it looks fine. This kind of thing, (Alamy previews,) bothered me at first but I don't pay it much mind anymore.

[The Blinking Eye]

7 minutes ago, jodyko said:

I don't think they ever disappear. I did something similar early on and the photo is still in my image manager though clearly marked as deleted.

 

Wouldn't worry about it personally but you might reinspect before re-submitting to put yourself at ease. I've noticed blockiness in the skies on the previews, some from very experienced contributors. On my monitor it looks fine. This kind of thing, (Alamy previews,) bothered me at first but I don't pay it much mind anymore.

 

I had a few that finally disappeared. They say they will be deleted within 180 days, so that's about 6 months.

 

OK thanks. I'm trying to be more careful as I noticed a dust spot on one of my uploads recently.

[Bill Brooks]

The chunkiness in the sky may be within QC tolerances but that does not mean it is good.

 

The image has a saturated blue sky. This means it has less information than a not so saturated blue sky. The lack of information in saturated colours, where colours are not graduated but make big jumps, makes the saturated sky look chunky.

 

Why does a saturated sky have less information than a less saturated sky and is prone to chunkiness, or abrupt changes in colour and brightness?

 

The digital file is a combination of RGB channels. Red Green Blue channels. Each channel can vary from 0 to 255 to give us, in combination at each pixel, all the colours of the rainbow.

 

A not so saturated blue sky, but still a blue sky, might have values of Red between 10 and 70, Green between 100 and 200, Blue between 180 and 254.

These values in an unsaturated blue sky will combine to create many values of blue and many values of brightness, so the sky will have considerable variation in its blues and brightness, and not look chunky.

 

Looking at the saturated blue sky part of your image:

 

The Red channel may have a value of 0. No Red. This means the Red is completely without variance. If the values were from 0 to 50 it would have some red variance

 

The Green channel may have a value that varies between 100 and 150. This provides some variance so you can see slightly different blues when the Green channel is combined with the Blue and Red channel.

 

The Blue channel has a value of 255 only. This means it is maximum blue so there is no blue variance.

 

In your sky the only variance is in the Green channel. This means that your variance information is in one channel only, not in all 3. The Green channel cannot make up for the variance lost in the RED and Blue channel. This makes the sky part of the image look chunky.

 

Saturated skies happen. A solution is to add a low level of noise to the image. Level 1.5 in photoshop. This noise will add enough variance in all 3 channels to suppress the chunkiness in the sky.

 

The jpg file format then compresses the information resulting in more chunkiness. To compress information it throws out small variances. So it may decide a variance of between 125 and 126 in the Green channel is insignificant. Two adjacent pixels no longer vary, they become the same colour. However it is significant in this image because all the variance information is only in the Green channel. Chunky disaster.!!

 

When I have a saturated blue sky image I add a bit of noise in photoshop, before I output the JPG. Noise is usually the enemy, but sometimes it is your friend.

 

Any saturated colour, a saturated red shirt for instance, can have the same chunkiness.

 

This is one argument for shooting RAW and not shooting JPG when shooting stock.

 

As others have said, Alamy JPG compression is also adding to the chunkiness.

 

Do not get too discouraged by technical details, as your Blinking Eye has a great eye for the image. Your images are great. Technical can be learned, having a great eye is not so easy.
 

[Johnnie5]

1 hour ago, The Blinking Eye said:

Thanks everyone. Still feel like I'm muddling through this process.

That feeling goes away in 5 to 10 years mostly😁

[M.Chapman]

10 hours ago, Bill Brooks said:

The chunkiness in the sky may be within QC tolerances but that does not mean it is good.

 

The image has a saturated blue sky. This means it has less information than a not so saturated blue sky. The lack of information in saturated colours, where colours are not graduated but make big jumps, makes the saturated sky look chunky.

 

Why does a saturated sky have less information than a less saturated sky and is prone to chunkiness, or abrupt changes in colour and brightness?

 

The digital file is a combination of RGB channels. Red Green Blue channels. Each channel can vary from 0 to 255 to give us, in combination at each pixel, all the colours of the rainbow.

 

A not so saturated blue sky, but still a blue sky, might have values of Red between 10 and 70, Green between 100 and 200, Blue between 180 and 254.

These values in an unsaturated blue sky will combine to create many values of blue and many values of brightness, so the sky will have considerable variation in its blues and brightness, and not look chunky.

 

Looking at the saturated blue sky part of your image:

 

The Red channel may have a value of 0. No Red. This means the Red is completely without variance. If the values were from 0 to 50 it would have some red variance

 

The Green channel may have a value that varies between 100 and 150. This provides some variance so you can see slightly different blues when the Green channel is combined with the Blue and Red channel.

 

The Blue channel has a value of 255 only. This means it is maximum blue so there is no blue variance.

 

In your sky the only variance is in the Green channel. This means that your variance information is in one channel only, not in all 3. The Green channel cannot make up for the variance lost in the RED and Blue channel. This makes the sky part of the image look chunky.

 

Saturated skies happen. A solution is to add a low level of noise to the image. Level 1.5 in photoshop. This noise will add enough variance in all 3 channels to suppress the chunkiness in the sky.

 

The jpg file format then compresses the information resulting in more chunkiness. To compress information it throws out small variances. So it may decide a variance of between 125 and 126 in the Green channel is insignificant. Two adjacent pixels no longer vary, they become the same colour. However it is significant in this image because all the variance information is only in the Green channel. Chunky disaster.!!

 

When I have a saturated blue sky image I add a bit of noise in photoshop, before I output the JPG. Noise is usually the enemy, but sometimes it is your friend.

 

Any saturated colour, a saturated red shirt for instance, can have the same chunkiness.

 

This is one argument for shooting RAW and not shooting JPG when shooting stock.

 

As others have said, Alamy JPG compression is also adding to the chunkiness.

 

Do not get too discouraged by technical details, as your Blinking Eye has a great eye for the image. Your images are great. Technical can be learned, having a great eye is not so easy.
 

 

That's interesting. Although your description maybe spot on with saturated blue skies, when I look at the image in question WP7AY2 (by taking a screenshot of the enlarged Alamy preview) I don't see any of the RGB values you mention. For example the sky just above the right hand spire reports (on my system) as RGB 27,40,106 and HSL 230, 74%, 42%.

 

Maybe at some point during processing the sky was close to fully saturated but, on my system, the sky in the enlarged Alamy preview image appears to be only 74% saturated. Am I doing something wrong? How are you getting those RGB values?

 

Looking the original jpg as uploaded of my own image (F5KR0T that shows blockiness on the Alamy preview but not in the jpg) it's only 49% saturated.

 

It looks like some compression or conversion is happening with Alamy previews which is causing the "effect". Actually I'd call it a "problem" as it's not making the images look very good. What's the point of stringent Alamy QC if they then degrade our images before displaying them to customers? If I submitted images that looked that blocky I'd expect a QC fail. Discerning customers may also be deterred from buying. I think this potentially merits further investigation. 

 

For example - Alamy's conversion of 8 bit AdobeRGB images to sRGB isn't ideal. Adjustments like that are best done on 16 bit images.

 

Mark

Edited October 6, 2019 by M.Chapman

[Mr Standfast]

9 hours ago, Bill Brooks said:

The chunkiness in the sky may be within QC tolerances but that does not mean it is good.

 

The image has a saturated blue sky. This means it has less information than a not so saturated blue sky. The lack of information in saturated colours, where colours are not graduated but make big jumps, makes the saturated sky look chunky.

 

Why does a saturated sky have less information than a less saturated sky and is prone to chunkiness, or abrupt changes in colour and brightness?

 

The digital file is a combination of RGB channels. Red Green Blue channels. Each channel can vary from 0 to 255 to give us, in combination at each pixel, all the colours of the rainbow.

 

A not so saturated blue sky, but still a blue sky, might have values of Red between 10 and 70, Green between 100 and 200, Blue between 180 and 254.

These values in an unsaturated blue sky will combine to create many values of blue and many values of brightness, so the sky will have considerable variation in its blues and brightness, and not look chunky.

 

Looking at the saturated blue sky part of your image:

 

The Red channel may have a value of 0. No Red. This means the Red is completely without variance. If the values were from 0 to 50 it would have some red variance

 

The Green channel may have a value that varies between 100 and 150. This provides some variance so you can see slightly different blues when the Green channel is combined with the Blue and Red channel.

 

The Blue channel has a value of 255 only. This means it is maximum blue so there is no blue variance.

 

In your sky the only variance is in the Green channel. This means that your variance information is in one channel only, not in all 3. The Green channel cannot make up for the variance lost in the RED and Blue channel. This makes the sky part of the image look chunky.

 

Saturated skies happen. A solution is to add a low level of noise to the image. Level 1.5 in photoshop. This noise will add enough variance in all 3 channels to suppress the chunkiness in the sky.

 

The jpg file format then compresses the information resulting in more chunkiness. To compress information it throws out small variances. So it may decide a variance of between 125 and 126 in the Green channel is insignificant. Two adjacent pixels no longer vary, they become the same colour. However it is significant in this image because all the variance information is only in the Green channel. Chunky disaster.!!

 

When I have a saturated blue sky image I add a bit of noise in photoshop, before I output the JPG. Noise is usually the enemy, but sometimes it is your friend.

 

Any saturated colour, a saturated red shirt for instance, can have the same chunkiness.

 

This is one argument for shooting RAW and not shooting JPG when shooting stock.

 

As others have said, Alamy JPG compression is also adding to the chunkiness.

 

Do not get too discouraged by technical details, as your Blinking Eye has a great eye for the image. Your images are great. Technical can be learned, having a great eye is not so easy.
 

Thank you Bill

[The Blinking Eye]

On 05/10/2019 at 16:08, Bill Brooks said:

The chunkiness in the sky may be within QC tolerances but that does not mean it is good.

 

The image has a saturated blue sky. This means it has less information than a not so saturated blue sky. The lack of information in saturated colours, where colours are not graduated but make big jumps, makes the saturated sky look chunky.

 

Why does a saturated sky have less information than a less saturated sky and is prone to chunkiness, or abrupt changes in colour and brightness?

 

The digital file is a combination of RGB channels. Red Green Blue channels. Each channel can vary from 0 to 255 to give us, in combination at each pixel, all the colours of the rainbow.

 

A not so saturated blue sky, but still a blue sky, might have values of Red between 10 and 70, Green between 100 and 200, Blue between 180 and 254.

These values in an unsaturated blue sky will combine to create many values of blue and many values of brightness, so the sky will have considerable variation in its blues and brightness, and not look chunky.

 

Looking at the saturated blue sky part of your image:

 

The Red channel may have a value of 0. No Red. This means the Red is completely without variance. If the values were from 0 to 50 it would have some red variance

 

The Green channel may have a value that varies between 100 and 150. This provides some variance so you can see slightly different blues when the Green channel is combined with the Blue and Red channel.

 

The Blue channel has a value of 255 only. This means it is maximum blue so there is no blue variance.

 

In your sky the only variance is in the Green channel. This means that your variance information is in one channel only, not in all 3. The Green channel cannot make up for the variance lost in the RED and Blue channel. This makes the sky part of the image look chunky.

 

Saturated skies happen. A solution is to add a low level of noise to the image. Level 1.5 in photoshop. This noise will add enough variance in all 3 channels to suppress the chunkiness in the sky.

 

The jpg file format then compresses the information resulting in more chunkiness. To compress information it throws out small variances. So it may decide a variance of between 125 and 126 in the Green channel is insignificant. Two adjacent pixels no longer vary, they become the same colour. However it is significant in this image because all the variance information is only in the Green channel. Chunky disaster.!!

 

When I have a saturated blue sky image I add a bit of noise in photoshop, before I output the JPG. Noise is usually the enemy, but sometimes it is your friend.

 

Any saturated colour, a saturated red shirt for instance, can have the same chunkiness.

 

This is one argument for shooting RAW and not shooting JPG when shooting stock.

 

As others have said, Alamy JPG compression is also adding to the chunkiness.

 

Do not get too discouraged by technical details, as your Blinking Eye has a great eye for the image. Your images are great. Technical can be learned, having a great eye is not so easy.
 

 

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.

 

And THANK YOU for the encouraging feedback. That makes me feel really good. I've been working super hard on upping my game as a photographer and also learning to be especially picky about what photos I offer to the public. Simply picking and choosing the best photos is a skill I underestimated so, as you can see, my portfolio here is improving.

[M.Chapman]

Ok I did some testing to find out what's actually going on here. I took one of my original jpgs (which was uploaded to Alamy and has a nice clean sky) and compared it with the "blocky" version shown by the Alamy preview. If I resize my original jpg in PS to match the size of the Alamy preview, and then save at jpg quality level 5 the blockiness appears in the sky and resulting image is a pretty close match to the Alamy preview.

 

So I think it's clear, Alamy is generating and storing preview images as lower quality level jpgs (as suggested by Colin Woods above). They are presumably doing this to economise and storage and maximise website responsiveness. It's a shame this can make some of the blue skies in our carefully prepared images look "blocky". I hope customers aren't put off. I have similar images on a micro-stock site and they don't appear to show this problem. 

 

Another part of the ongoing race to add more and more images having an impact on quality??

 

Mark

Edited October 7, 2019 by M.Chapman