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M.Chapman

Useful sRGB AdobeRGB test images?

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1 hour ago, M.Chapman said:

(It's such a shame they have already discarded any wide gamut information in the images they have in the library, so they have to start from scratch*)

Certainly is, but do we know that for sure? Is it possible that the conversion and stripping of profile is done at the point of download? 

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1 hour ago, M.Chapman said:

The displays in John Lewis etc.  look really impressive, but I'm wary that they are also showing images and videos that have been artificially "pumped up" in terms of sharpening and saturation.

It's sacrilegious in colour management terms to suggest this but I also find myself wondering what an image would look like on such TV/Cinema screens if it had been converted from sRGB to AdobeRGB or P3. Totally unsound from a technical point of view of course. I should try it on my 'wide gamut' Dell and I will once I catch up with the current scanning project! Still there's a difference between careful analysis in a 'studio' setting and looking at an image on a big telly.

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51 minutes ago, Harry Harrison said:

Certainly is, but do we know that for sure? Is it possible that the conversion and stripping of profile is done at the point of download? 

 

I think the conversion and profile strip is done at the point of receipt, but I'd have to dig back into my notes/emails with Alamy to be 100% sure. 

I imagine the further compression and generation of lower res thumbnails is probably all done at the same time.

 

That's not to say they didn't keep an offline "archive" copy of what we submitted though....

 

Mark

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Posted (edited)
1 hour ago, Harry Harrison said:

It's sacrilegious in colour management terms to suggest this but I also find myself wondering what an image would look like on such TV/Cinema screens if it had been converted from sRGB to AdobeRGB or P3. Totally unsound from a technical point of view of course. I should try it on my 'wide gamut' Dell and I will once I catch up with the current scanning project! Still there's a difference between careful analysis in a 'studio' setting and looking at an image on a big telly.

 

I just tried what you suggest. If an sRGB image is correctly tagged, and then converted to AdobeRGB and also correctly tagged, then the appearance is unchanged (all the sRGB colours in the original can be displayed in AdobeRGB space - although some extra banding may appear in subtle gradients due to extra compression). The colours are lost when AdobeRGB is converted to sRGB (that's the most "sacrilegious" bit).

 

I notice in the Apple video it also said P3 Gamut images had to be saved as PNG format for web-use to retain both 16bit and the profile info. I wonder if that's still the case, or does Apple's new HEIC/HEIF format now provide an alternative? (Although I imagine many web bowsers don't support this).

 

Mark

Edited by M.Chapman

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52 minutes ago, M.Chapman said:

 

I think the conversion and profile strip is done at the point of receipt, but I'd have to dig back into my notes/emails with Alamy to be 100% sure. 

I imagine the further compression and generation of lower res thumbnails is probably all done at the same time.

 

That's not to say they didn't keep an offline "archive" copy of what we submitted though....

 

Mark

 

When I first joined Alamy we had to submit in TIF format.  If I look at my earliest submissions in Image Manager, dating from 2001, they are still showing as TIFs, so I assume that they are as originally supplied.

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2 hours ago, M.Chapman said:

and then converted to AdobeRGB and also correctly tagged, then the appearance is unchanged

I was really thinking about how it would look on a wide gamut display or Retina screen or Iphone  7 onwards etc. As I understand it the sRGB colour numbers would be remapped/expanded to fill the larger colour space and colours invented in between. It's clearly wrong to do it, converting/remapping from the larger AdobeRGB colour space down to sRGB is fine but not the other way round obviously, but I'm curious how it looks so I might try it. Start with an Adobe RGB file, convert to sRGB, convert that back to AdobeRGB and compare with the original file on a wide gamut screen just to get a handle on what the degradation looks like, can't look at it on Retina though. I think I'd have to be in the right mood though....

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2 hours ago, Vincent Lowe said:

When I first joined Alamy we had to submit in TIF format.  If I look at my earliest submissions in Image Manager, dating from 2001, they are still showing as TIFs, so I assume that they are as originally supplied.

Now that's interesting, could be very relevant. 

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2 hours ago, Vincent Lowe said:

When I first joined Alamy we had to submit in TIF format.  If I look at my earliest submissions in Image Manager, dating from 2001, they are still showing as TIFs, so I assume that they are as originally supplied.

It could I suppose just be a record of the original filename recorded on the database at the time of upload.

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6 minutes ago, Harry Harrison said:

It could I suppose just be a record of the original filename recorded on the database at the time of upload.

 

Good point - I suppose there's no way of knowing for certain unless Alamy chip in....:unsure:

 

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2 hours ago, Harry Harrison said:

As I understand it the sRGB colour numbers would be remapped/expanded to fill the larger colour space and colours invented in between.

 

Not if the sRGB image is correctly tagged it shouldn't. That's the point of colour management. Now if you ignored the sRGB tag and assigned AdobeRGB or P3 profile instead (easy to do in PS), then the sRGB image will "expand" into AdobeRGB or P3 space. But doing that is "sacreligious"... 

 

Mark

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5 hours ago, Vincent Lowe said:

 

When I first joined Alamy we had to submit in TIF format.  If I look at my earliest submissions in Image Manager, dating from 2001, they are still showing as TIFs, so I assume that they are as originally supplied.

 

Pure guesswork on my part, but given the customer will receive a jpg (not a TIFF), I suspect Alamy will have converted the large TIFFs to smaller jpgs and the original filename is just stored in the database for reference only. 

 

Mark

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1 hour ago, M.Chapman said:

Not if the sRGB image is correctly tagged it shouldn't. That's the point of colour management. Now if you ignored the sRGB tag and assigned AdobeRGB or P3 profile instead (easy to do in PS), then the sRGB image will "expand" into AdobeRGB or P3 space. But doing that is "sacreligious"... 

 

Well, that's not how I see it actually, if you 'assign' a different colour profile then the underlying colour numbers (RGB values) stay the same, the file is not changed but the colour numbers are interpreted with respect to the alternative colour space and so the colours will become more vivid or more muted accordingly in simple terms. If you've done it by mistake then it's no problem, just assign the correct profile, no harm done.

 

If you 'convert' a profile then the underlying colour numbers are changed in order to represent the image correctly in this different, normally smaller, colour space, so in our example converting from Adobe RGB to sRGB should mean that the appearance of the image doesn't change markedly. However I don't think that you can then take this sRGB file, now with its modified colour numbers, and expect to be able to convert it back to Adobe RGB without some degradation and I'm just mildly interested to see how this degradation might manifest itself, quite possibly in banding I suppose. Note I'm talking about saved jpegs here, obviously you can go backwards and forwards with a RAW file as often as you like because the RAW file is never changed.

 

That's how I see it anyway.

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1 hour ago, Harry Harrison said:

Well, that's not how I see it actually, if you 'assign' a different colour profile then the underlying colour numbers (RGB values) stay the same, the file is not changed but the colour numbers are interpreted with respect to the alternative colour space and so the colours will become more vivid or more muted accordingly in simple terms. If you've done it by mistake then it's no problem, just assign the correct profile, no harm done.

 

If you 'convert' a profile then the underlying colour numbers are changed in order to represent the image correctly in this different, normally smaller, colour space, so in our example converting from Adobe RGB to sRGB should mean that the appearance of the image doesn't change markedly. However I don't think that you can then take this sRGB file, now with its modified colour numbers, and expect to be able to convert it back to Adobe RGB without some degradation and I'm just mildly interested to see how this degradation might manifest itself, quite possibly in banding I suppose. Note I'm talking about saved jpegs here, obviously you can go backwards and forwards with a RAW file as often as you like because the RAW file is never changed.

 

That's how I see it anyway.


I think that is broadly correct. Assigning a profile does nothing to the image so is effectively the same as changing the colour space on a monitor that has that facility. From my reading of Martin Evening, it is useful if one receives an untagged  image to envisage what was intended but does not change the colours.
 

Converting from a smaller to a larger colour space is not something I do purposely but I guess the outcome would be unpredictable and might be more appropriately called colour mismanagement. Viewing an sRGB or AdobeRGB image that has been saved outside of Lightroom and then Imported and further edited in Lightroom would I guess be expanding the colour space as Lightroom has a huge colour space close to ProPhoto. Adobe purposely took colour management in Lightroom out of the users’ hands to make life simple which is what Alamy has done as well in a somewhat different way. 
 

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Posted (edited)
3 hours ago, Harry Harrison said:

Well, that's not how I see it actually, if you 'assign' a different colour profile then the underlying colour numbers (RGB values) stay the same, the file is not changed but the colour numbers are interpreted with respect to the alternative colour space and so the colours will become more vivid or more muted accordingly in simple terms. If you've done it by mistake then it's no problem, just assign the correct profile, no harm done.

 

If you 'convert' a profile then the underlying colour numbers are changed in order to represent the image correctly in this different, normally smaller, colour space, so in our example converting from Adobe RGB to sRGB should mean that the appearance of the image doesn't change markedly. However I don't think that you can then take this sRGB file, now with its modified colour numbers, and expect to be able to convert it back to Adobe RGB without some degradation and I'm just mildly interested to see how this degradation might manifest itself, quite possibly in banding I suppose. Note I'm talking about saved jpegs here, obviously you can go backwards and forwards with a RAW file as often as you like because the RAW file is never changed.

 

That's how I see it anyway.

 

I think we agree on the principles.

 

You wondered about the effect of converting and sRGB image to the larger AdobeRGB colour space. Two things happen when doing this. Firstly the sRGB image data in the file is compressed slightly, to leave room for the extra colours in the AdobeRGB gamut (that aren't there in this case). The AdobeRGB profile is then applied which expands the data back out ready to be displayed. The compression and expansion are mathematically inverse processes and nominally perfect (apart from a slight the loss of precision if it's 8 bit data). It's simple to try this for yourself. When you convert an sRGB image to an AdobeRGB image you will see no significant change (it doesn't matter whether you have an sRGB or AdobeRGB monitor). This process is doing exactly what it should, the system is trying to preserve the appearance of the image when converting from one colour space to a larger colour space.

 

Going in the other direction ie. converting AdobeRGB to sRGB is moving to a smaller colour space and, if there are colours in the AdobeRGB image that are outside the destination sRGB space, they will be lost (typically clipped). The precise way the image change in appearance depends on the conversion settings perceptual/absolute colorimetric/relative colorimetric etc. 

 

You are also right that profile assignment leaves the image data alone. It simply determines the way the data is interpreted / displayed. If the data was encoded in sRGB colour space and shipped without a profile (as Alamy do) then assigning an sRGB profile is the correct thing to do. No matter what type of monitor you have.

 

But assigning a different profile to one used to encode the image data is going to misinterpret the data. It's a bit like somebody sends you a file of speeds in km/hr. But you interpret the file as if it contains speeds in mph. You'll get the wrong result. There are times when folks will prefer the misinterpreted results (wow the car goes faster - or the colours are richer) .... but it's not a very legitimate thing to do. Unfortunately I suspect quite a few Alamy customers may be doing this inadvertently. If they open an Alamy file (with no profile) in an Adobe product which is set to use a default colour space of AdobeRGB (and they have the missing profile warning dialogs turned off) they will interpret Alamy sRGB data as if it's AdobeRGB and see a more intense image than they should. 

 

It's easy to test all these things in PS. You may also find this useful https://turbofuture.com/graphic-design-video/SRGB-AdobeRGB-and-ProPhotoRGB-colour-spaces

 

Mark

 

Edited by M.Chapman

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Posted (edited)
2 hours ago, MDM said:

Converting from a smaller to a larger colour space is not something I do purposely but I guess the outcome would be unpredictable and might be more appropriately called colour mismanagement.

 

Going that way is totally predictable. I wouldn't call it "mismanagement", (assigning the wrong profile or ignoring the profile is mismanagement). In fact this process is exactly what happens when merging two images when one is sRGB and the other is AdobeRGB. Suppose we have an AdobeRGB image that we want to add something from an sRGB image (e.g. cut and paste). PS will give a warning;

 

Paste Profile Mismatch

You are pasting content for a document with a different profile

Source: sRGB

Destination: AdobeRGB

What would you like to do?

(1) Convert (preserve colour appearance)

(2) Don't convert (preserve colour numbers)

 

(1) is normally used for photos

(2) maybe useful for graphic designers

 

Mark

 

Edited by M.Chapman

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15 minutes ago, M.Chapman said:

You are also right that profile assignment leaves the image data alone. It simply determines the way the data is interpreted / displayed. If the data was encoded in sRGB colour space and shipped without a profile (as Alamy do) then assigning an sRGB profile is the correct thing to do. No matter what type of monitor you have.

 

 

 

I'm not so sure. Assigning a profile will not do anything beyond showing you what the image would look like in sRGB space. Knowing what we know about Alamy converting to sRGB and then removing the profile, surely it would be better to use an sRGB workspace in Photoshop and convert the untagged image to sRGB when opening. Or convert to profile having opened it as untagged.

 

To be honest I almost never use any of these operations anyway as I have a very straightforward workflow between Lightroom and Photoshop so this stuff never comes up for me. Worrying about how my images look on Alamy or as bought by Alamy suppliers is not worth the time of day for my tired brain as there is absolutely nothing I can do about it. My last sale was for a record low $3 for a rights managed image to be used in perpetuity worldwide by the travel sector brings this into focus. 

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Posted (edited)

If you try to open an untagged image (e.g. from Alamy) in PS, and have your colour management policy set to (Missing profiles: - Ask when opening), PS will ask you what you want to do.

 

Missing Profile

Leave as is (don't colour manage)

Assign Working Profile

Assign Profile of your choice.

 

With images from Alamy, the correct decision is to Assign sRGB (which may or may not be your working space/default profile). Anything else will give an incorrectly rendered image. 

 

8 hours ago, MDM said:

Worrying about how my images look on Alamy or as bought by Alamy suppliers is not worth the time of day for my tired brain as there is absolutely nothing I can do about it. My last sale was for a record low $3 for a rights managed image to be used in perpetuity worldwide by the travel sector brings this into focus. 

 

Oh dear how disheartening. Nevertheless, in spite of falling revenues, I'll continue to care about how my images look on Alamy (which I absolutely can do something about) and to customers. Otherwise, in a competitive "sea" of over 200M images, I fear there's little point in trying to sell images here at all.

 

Mark

Edited by M.Chapman

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Posted (edited)
13 hours ago, MDM said:

Converting from a smaller to a larger colour space is not something I do purposely but I guess the outcome would be unpredictable and might be more appropriately called colour mismanagement.

My example really is that going from AdobeRGB to sRGB and then back from sRGB to AdobeRGB is not a lossless process in certain circumstances, but I'll explain below.

 

11 hours ago, M.Chapman said:

You wondered about the effect of converting and sRGB image to the larger AdobeRGB colour space. Two things happen when doing this. Firstly the sRGB image data in the file is compressed slightly, to leave room for the extra colours in the AdobeRGB gamut (that aren't there in this case). The AdobeRGB profile is then applied which expands the data back out ready to be displayed.

I think maybe I'm not explaining myself properly, I think we're all singing off the same hymn sheet, which is good as there's only one Colour Management hymn.

 

I was really wondering about your proposition that Alamy should offer Adobe RGB images given that wider gamut screens are becoming mainstream, particularly in the Apple ecosphere - if it would be a sound business move. That made me think about what might be lost when you convert an sRGB image to AdobeRGB compared to the original AdobeRGB image that the photographer might have had available but didn't upload, or they uploaded and it was converted to sRGB.

 

This is what I'm thinking:

I set my camera to record jpegs in the AdobeRGB colour space,  I photograph a rich colourful scene that captures colours that would have been outside of the sRGB colour space. These colours cannot be seen on an sRGB monitor but could be printed on a modern quality inkjet photo printer.

 

I convert this file to sRGB for upload to Alamy, so far so good.

 

By some miracle someone actually buys my image but they decide to convert it to AdobeRGB or even P3. 

 

How would their converted image compare visually to my original AdobeRGB jpeg?

 

My point is really that the existing sRGB colours in the downloaded image can all be remapped to their correct positions in the AdobeRGB colour space precisely.  However the colours in the original image that fell outside of the sRGB colour space (that wouldn't have been visible on an sRGB display) have already been thrown away in the conversion from AdobeRGB to sRGB, they can't be recreated, only approximated.

 

So I was wondering  how the two images would compare side by side on a Wide Gamut or Retina screen, original 'As Shot' AdobeRGB image v. downloaded sRGB image converted back to AdobeRGB.

 

 

 

 

Edited by Harry Harrison

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Posted (edited)
2 hours ago, M.Chapman said:

If you try to open an untagged image (e.g. from Alamy) in PS, and have your colour management policy set to (Missing profiles: - Ask when opening), PS will ask you what you want to do.

 

Missing Profile

Leave as is (don't colour manage)

Assign Working Profile

Assign Profile of your choice.

 

With images from Alamy, the correct decision is to Assign sRGB (which may or may not be your working space/default profile). Anything else will give an incorrectly rendered image. 

 

 

Oh dear how disheartening. Nevertheless, in spite of falling revenues, I'll continue to care about how my images look on Alamy (which I absolutely can do something about) and to customers. Otherwise, in a competitive "sea" of over 200M images, I fear there's little point in trying to sell images here at all.

 

Mark

 

I think there is a terminology problem here. Adobe’s terminology is confusing, in their help file as well. As far as I am aware that 3rd option in the opening dialog is effectively converting to a profile of your choice, not assigning as in the Edit - Assign Profile command  as far as I know. It was the latter command that I was referring to in all my previous posts. 

 

My point in relation to worrying about Alamy’s colour management policy is that it is futile to do so as nothing is going to change. Subject matter and overall processing are going to override any differences related to the colour profile or colour space used in processing the images. In addition one has no control at all about how the images are subsequently viewed or treated by a buyer or viewer so getting worked up about it is futile as nothing will change. I think you are on a one man mission to nowhere if you let Alamy's colour management policy worry you at all. 

 

For me I am a pragmatic perfectionist. I think it is always worthwhile producing images to the best of one’s ability and that is what I try to do but focusing on how they will look on Alamy is not a priority for me. 

 

 

Edited by MDM

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Posted (edited)
On 13/06/2020 at 09:06, MDM said:

I think there is a terminology problem here. Adobe’s terminology is confusing, in their help file as well. As far as I am aware that 3rd option in the opening dialog is effectively converting to a profile of your choice, not assigning as in the Edit - Assign Profile command  as far as I know. It was the latter command that I was referring to in all my previous posts. 

 

Adobe's terminology appears right to me (within the software) and does what it says on the tin (it's easy to test if you have a file without a profile). When opening an image without a profile, the convert option is also shown (see bleow). Sorry, I missed that line out from my posting above. You have to assign a profile first (so the software knows how to decode the image data in the file) and then you can convert to your working space. To get images purchased from Alamy to render correctly in PS, customers must either explicitly assign an sRGB profile, or they can open open as unmanaged if their working space is set to sRGB because PS will, under those circumstances, assume sRGB. NB. I know that this works because of the test images I downloaded from Alamy.

 

Dialog.png

 

Mark

Edited by M.Chapman

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1 hour ago, MDM said:

My point in relation to worrying about Alamy’s colour management policy is that it is futile to do so as nothing is going to change. Subject matter and overall processing are going to override any differences related to the colour profile or colour space used in processing the images. In addition one has no control at all about how the images are subsequently viewed or treated by a buyer or viewer so getting worked up about it is futile as nothing will change. I think you are on a one man mission to nowhere if you let Alamy's colour management policy worry you at all. 

 

You may well be right that Alamy are unlikely to change their colour management policy (too many legacy images) based on a "one man mission". But I'm not the only one that thinks it would be beneficial if they did change it. In the meantime, what I can do, is comply with their current policy - and upload the best images I can by making final edits and uploading in sRGB. Don't get me wrong, I want to transition to wide gamut (the market is going that way - and I believe Alamy, if it survives, will eventually follow), but at the moment, the libraries I supply images to require sRGB.

 

Mark 

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Posted (edited)
24 minutes ago, M.Chapman said:

 

Adobe's terminology appears right to me (within the software) and does what it says on the tin (it's easy to test if you have a file without a profile). When opening an image without a profile, the convert option is also shown (see bleow). Sorry, I missed that line out from my posting above. You have to assign a profile first (so the software knows how to decode the image data in the file) and then you can convert to your working space. To get images purchased from Alamy to render correctly in PS, customers must either explicitly assign an sRGB profile, or they can open open as unmanaged if your working space is set to sRGB because PS will, under those circumstances, assume sRGB. NB. I know that this works because of the test images I downloaded from Alamy.

 

Dialog.png

 

Mark

That is different to what I was  talking about. If I have my colour management policy set to now ask when opening for documents with missing profiles, this dialog will not show up. If I open the untagged file. then use the Edit-Assign Profile command, it does nothing to the colour numbers. Adobe use the term assign in different ways in their help file for sure. I just read it yesterday.

 

The bottom line here is that it is not possible to know how other people will view your images because there are so many variables: type of device, calibrated or not, software type, software settings, treatment,  and so on. I believe it is a waste of time and energy worrying about how others will view your images from a colour management perspective as it is out of your control.

 

By all means work in sRGB if that suits your workflow. I will work in AdobeRGB because that suits mine. There is no way Alamy are going to change this.  I don't think many contributors care too much or have much understanding of this anyway and I don't think we will be seeing mass demonstrations in Oxford for this reason. People who work in Lightroom only are effectively working in ProPhoto RGB and then exporting with whatever profile without ever thinking about colour management.

 

I think we have beaten this thing to death now in any case. Time to process some images and move on.

Edited by MDM

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15 minutes ago, MDM said:

If I have my colour management policy set to now ask when opening for documents with missing profiles, this dialog will not show up. 

 

That's interesting. Something's wrong there then. Maybe, although your document doesn't have the profile embedded, it still has a profile tag? I can send you an image from Alamy if you like to try that which has no profile or tag.

 

Mark

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Posted (edited)

Sorry there was a typo. It should have read NOT ASK WHEN OPENING, not NOW ASK. 

Edited by MDM

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Posted (edited)
40 minutes ago, MDM said:

If I open the untagged file. then use the Edit-Assign Profile command, it does nothing to the colour numbers. Adobe use the term assign in different ways in their help file for sure. I just read it yesterday.

 

I'm sorry I think you are still misunderstanding what assigning and converting (in the software) actually do. The colour numbers are the values in the file, before the profile is applied. Applying a profile leaves the colour numbers unchanged, but may change what appears on screen. Converting changes the colour numbers, but when the new profile is applied the colours on screen shouldn't change.

 

Mark

Edited by M.Chapman

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