Author Topic: Jpeg and isolation? (Read 6259 times)

vonkara · « **on:** February 21, 2008, 16:12 »

I just discover that some of my isolation whit the pen tool was correct just before saving them.

But after saving them at the maximum quality ... I open the saved file reselect the 255 background (select tool always at 0) and then I see several areas who aren't properly isolated.

I don't know what to do...I'm a bit lost on what do this. Maybe it's because it's a Jpeg file and the quality decline after the save.

I also think that when I select the size in the saving option from 28.8 to 56.6 the new infos don't have the time to load. But I really don't know which way to look first?

araminta · « **Reply #1 on:** February 21, 2008, 16:32 »

Quote from: Vonkara on February 21, 2008, 16:12

Maybe it's because it's a Jpeg file and the quality decline after the save.

I don't think JPEG compression would add artifacts in pure white regions.

leszek · « **Reply #2 on:** February 21, 2008, 16:52 »

"I don't think JPEG compression would add artifacts in pure white regions. "

It does. Little ghosts appear around the isolated object, close to its boundary. Setting threshold to 1 or 2 gets rid of them (when selecting 255,255,255) color. I guess this is what some of the reviewers are picking as "bad isolation" - which is incorrect.

vonkara · « **Reply #3 on:** February 21, 2008, 17:25 »

This is exactly what happen "little ghosts". So I know that upgrading the threshold will get over these imperfections and also probably the designer, but now I'm still afraid to get these rejected ?

Now the only thing I see is to reuse the first file and take another hour or hour a half and make the whole thing again. Next time I will take more caution. That will getting me more closer to the IS delirium club

When there will be the ultra-nanostock agencies where I will be able to submit pictures taken whit a webcam...end of complaint here

madelaide · « **Reply #4 on:** February 21, 2008, 17:57 »

Vonkara,

I had this problem in one rejection, though I make sure my whites are really whites in TIFF, they still get some type of

See this thread with the previous discussion (black background in my case):
http://www.microstockgroup.com/index.php/topic,3111.0.html

It is odd for a rejection as it seems inherent to JPEG compression that this happens (much to my surprise by then). Indeed, I checked other approved isolations and they all have this.

Regards,
Adelaide

vonkara · « **Reply #5 on:** February 21, 2008, 18:19 »

Thanks for sharing your experience. Did you resubmit the file or you just let thing like it is?

madelaide · « **Reply #6 on:** February 21, 2008, 21:20 »

I didn't resubmit because we were already so close to New Years. I should open a ticket though. I sold some 2007 images late in the year.

Regards,
Adelaide

leszek · « **Reply #7 on:** February 21, 2008, 23:04 »

Knowing that this happens - I also include clipping paths - so this should be a non-issue. But, it appears to be not sufficient in the eyes of some reviewers and images get knocked back for bad isolation. Go figure.

vonkara · « **Reply #8 on:** February 22, 2008, 10:21 »

I also find that including the path is at least the same as having a perfect isolation. It's becoming a bit absurd.

Another thing who become absurd is when I shoot macro. While the magnification is increasing, the focus range is decreasing and that's normal. I can increase the f stop, but that's play more and more whit the sharpness pass f/11 or f/13. Then it's the "to much of the image is out of focus".

But I honestly think that this is the macro world. It's difficult sometime to choose between dept of field and sharpness.?.

Waldo4 · « **Reply #9 on:** February 22, 2008, 11:51 »

I just had one rejected the other day for that reason, not enough DOF, at f/40, with my Tele at about closest focusing range at max zoom. I'm not sure if it is possible to get more DOF at that magnification, the shot is essentially an impossible capture for what they are looking for for DOF (dice falling out of a dice cup straight toward the viewer (slight offset) at table level, the front dice being in perfect focus, the cup having DOF effects though (about 2 inches behind the front dice)).

null · « **Reply #10 on:** February 22, 2008, 16:31 »

Quote from: Vonkara on February 21, 2008, 16:12

I just discover that some of my isolation whit the pen tool was correct just before saving them.

But after saving them at the maximum quality ... I open the saved file reselect the 255 background (select tool always at 0) and then I see several areas who aren't properly isolated.

Yap, I posted about it here and on the SS forum. I had examples but can't show them any more because I was banned on Flickr. Basically, it's a jpg artifact. Select the white with the Magic Wand Tool: tolerance 0, ant-alias and contiguous off. On the TIF you will see a nice isolation.

Save it as JPG maximal quality. Load that JPG and do the same. You will see small non-white (254,255,254 or so) dithers around the edge.

On SS I was advised to do clipping paths.

madelaide · « **Reply #11 on:** February 22, 2008, 16:50 »

Of my isolations (not that I have so many), it was the only one rejected in IS for that reason. Another image of the same series was approved and other images on white have no problem. I can't do clipping paths in PSP7.

About focus, when I use selective focus in my description I say something about that (such as "selective focus on pen"), so they know this is an intentional effect. I don't think I had any rejection for that. I had in a couple that weren't indeed quite sharp.

Regards,
Adelaide

vonkara · « **Reply #12 on:** February 22, 2008, 19:45 »

Quote from: madelaide on February 22, 2008, 16:50

I can't do clipping paths in PSP7.

OK, I'm quite a super newbie whit clipping path. I have the oldest photoshop dinosaur here whit the 6.0 version. I wonder to know exactly what is the clipping path? When I use the pen tool and close my selection, I go in layer.

Then I click on "path" where my selection is showing. Do that is the clipping path, because I can easily move my selection? But it's not showing the word clipping nowhere in 6.0? I'm quite lost at this point as I never at this time being able to see CS2 or 3 and compare. Any help would be appreciated.

madelaide · « **Reply #13 on:** February 22, 2008, 20:43 »

Clipping path is a selection that some software can embbed and read in a JPEG file. If the selection is done well, this would save the buyer the extra work of making selections.

In a previous thread it was said that resized images in the sites don't retain the clipping path. I can't tell. But if the quality of a clipping path is not checked in the inspection and if anyway anyone can add to their description "with clipping path" I don't think it make any difference for the buyer - it would only be a plus.

Regards,
Adelaide

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Author Topic: Jpeg and isolation? (Read 6259 times)

vonkara

araminta

leszek

vonkara

madelaide

vonkara

madelaide

leszek

vonkara

Waldo4

null

madelaide

vonkara

madelaide

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