dc10tim
Posts: 1380
Joined: Mon Jan 03, 2005 12:21 am

Black And White Smudge Marks

Mon Mar 28, 2005 7:19 am

Hello everyone,

I have noticed on a couple of shots that I've put in the upload queue recently, there are black and/or white smudge marks, usually down the left-hand side.

These are not apparent when you have the image in photoshop, but seem to appear once uploaded. I was wondering if anyone knew how they were caused and how they could be got rid of?

I have seen them on many other photographer's uploads too, so it wouldn't appear to be something I'm doing that creates the effect.

Here is the shot that brought the problem to my attention:


View Large View Medium
Click here for bigger photo!

Photo © Tim Goodwin



It's just a little frustrating when you've taken time to edit a shot to see this.

Regards,

Tim.
Obviously missing something....
 
DLKAPA
Posts: 7962
Joined: Wed Dec 03, 2003 10:37 am

RE: Black And White Smudge Marks

Mon Mar 28, 2005 7:26 am

Not seeing it.

and yes, this is a valuable edition to the topic.
And all at once the crowd begins to sing: Sometimes the hardest thing and the right thing are the same
 
Newark777
Posts: 8284
Joined: Thu Dec 02, 2004 6:23 am

RE: Black And White Smudge Marks

Mon Mar 28, 2005 8:00 am

If you are talking about the little black smudge on the left side of the thumbnail, that is just something that effects the picture when it is reduced in size. Press "large," and there is no black smudge anymore.

Harry
Why grab a Heine when you can grab a Busch?
 
dc10tim
Posts: 1380
Joined: Mon Jan 03, 2005 12:21 am

RE: Black And White Smudge Marks

Mon Mar 28, 2005 8:02 am

Just look down the left side of the thumbnail about halfway down.

Tim.
Obviously missing something....
 
Newark777
Posts: 8284
Joined: Thu Dec 02, 2004 6:23 am

RE: Black And White Smudge Marks

Mon Mar 28, 2005 8:29 am

Again, it is only the thumbnail, the result of some odd quirk when compressing the original photo. Enlarge the shot to its actual size, and it won't be there.

Harry
Why grab a Heine when you can grab a Busch?
 
dc10tim
Posts: 1380
Joined: Mon Jan 03, 2005 12:21 am

RE: Black And White Smudge Marks

Mon Mar 28, 2005 8:37 am

Harry,

Sorry, I didn't explain very well in the first post. I agree it's not there at the large size, nor the pre-uploaded image. It is possible to see it slightly at the medium size.

I was just wondering what caused it and if it could be avoided in future?

It's not a major problem, but I'd rather it not be there.

Regards,

Tim.
Obviously missing something....
 
Bobster2
Posts: 1523
Joined: Mon Jan 17, 2005 3:04 am

RE: Black And White Smudge Marks

Mon Mar 28, 2005 8:38 am

I think we should reject the thumbnail and medium images for BadSmudgeOnLeft.
"I tell you this, no eternal reward will forgive us now for wasting the dawn." Jim Morrison
 
Psych
Posts: 2944
Joined: Tue Nov 16, 2004 1:17 am

RE: Black And White Smudge Marks

Thu Apr 07, 2005 8:16 pm

It's great knowing Tim - he's even more obsessional than I am Big grin .

To his credit he didn't let this go until he resolved the dilemma. In good deductive style, Tim was able to establish that these 'smudges' on the edges of thumbnails occur when there is an image that is cropped in such a way that the subject is against one side of the image, has varying colours/contrasts and the other side of the image is 'open'. What then seems to occur is that a coloured bit of the image against the dark of one edge is mirrored by a kind of 'negative' or 'reciprocal' colour on the opposite open edge of the thumbnail - e.g. light on one side, dark on the other.

To illustrate, I trawled the whole database for a good example, and just happened to find one of my own photos  Wink :


View Large View Medium
Click here for bigger photo!

Photo © Paul Markman



Here you can see that the strips of colour intersecting the right hand edge of the image are replicated in a kind of negative/reciprocal colour on the left hand edge.

All fascinating stuff, and potentially completely irrelevant smile . As has already been said, this feature of the photo is not replicated in the larger images. I have tried to reassure Tim that he doesn't need to worry about this any longer and I understand he shall be discharged from therapy shortly  crazy . Seriously - I admire such an enquiring mind. Well done Tim for solving this challenge.

Paul
 
dc10tim
Posts: 1380
Joined: Mon Jan 03, 2005 12:21 am

RE: Black And White Smudge Marks

Fri Apr 08, 2005 2:31 am

Quoting Psych (Reply 7):
It's great knowing Tim - he's even more obsessional than I am .

Interesting. When I was at sixth-form college I was conscious of my friends who studied Psychology constantly trying to diagnose me Big grin

Thanks Paul for posting about the smudges, I was in two minds (figure of speech) whether to bother or not myself.

Now it seems it is possible to identify when the marks will appear. It would be nice if someone could come in and explain how or why they are produced in the first place.

I'm reassured anyway that it is not something that I can prevent, although I think they make the thumbnails a little untidy.

Regards,

Tim.
Obviously missing something....

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