How to get rid of artifacting?

<p>Hi everyone,<br>

I have a technical question: I've been trying to post some of my pictures on a stock website, and one hurdle i can't seem to pass is the artifacts problem. it seems to be in every picture I post.<br>

Any idea where that comes from and how to avoid or detect it?<br>

Thanks a lot! <br>

Here is an example:<br>

<img src="http://lh6.ggpht.com/_coLBVaCW98c/SviPrwD6rZI/AAAAAAAADG8/uO_zN9ahq7Y/s640/DSC_3981.JPG" alt="" /><br /><br /></p>

<p>Are you talking about the red line on the white house, where the white and the roof meet? That's called chromatic aberrations. If you shoot in raw, you can remove it with Adobe Raw in photoshop. You will have to play with the setting, but it's fixable.<br>

It happens with any consumer level lens.</p>

<p>It would really help if you could post a 100% crop of the area that has the artifacts.</p>

<p>Thanks Matt, I guess I'll have to look into that.</p>

<p>My problem (I am new to this) is that I don't even know where the artifacts are... I'll have a look at the picture at 100% crop and try to spot it....</p>

<blockquote>

<p>My problem (I am new to this) is that I don't even know where the artifacts are.</p>

</blockquote>

<p>Wait. HOW do you know there <em>is</em> an "artifacts problem" then? Is the stock company telling you so? or what?</p>

<p>It may be that you are simply trying to post images that are too low resolution for the site and getting pixelation or other effects of scale when it is blown up?</p>

<p>Could also be compressing the jpeg too much</p>

<p>Yes that's the feedback from the stock company. I think the resolution was OK but that's a good lead maybe I should look into that and into the level of Jpeg compression as well.</p>

<p>Thanks a lot for the replies!</p>

<p><img src="http://i34.tinypic.com/qwzt39.jpg" alt="" width="425" height="308" /></p>

<p>the artifact they're talking about is most likely what i've circled, that is a problem with Jpeg compression. If they're talking about the red line between the roof of the white house and its walls, that's chromatic abberation, that's something form the lens. you can remove it by using Adobe Light room or adobe photoshop CS5. select "lens profile", select your lens and the algorithm would try to correct it as much as possible. if your lens happens to be not in the preloaded lens profiles you can build a lens profile yourself by following their instructions... google custom lens profile adobe...</p>

<p>Why are you submitting a JPEG rather than something like a TIFF? Is that a requirement of the stock company, or just something you're doing?</p>

<p>It's possible to remove JPEG artifacts such as the type Lee Kee demonstrated in that magnified version. But it comes at a cost - loss of fine texture detail, unless you work in layers and apply JPEG compression artifact removal only where absolutely needed.</p>

<p>Best solution - avoid it in the first place. If you must submit only JPEGs for use by a stock agency, contest, etc., use minimal compression. Otherwise, submit photos in a lossless format.</p>

<p>I'm also seeing some ugly jaggies from oversharpening, possibly exaggerated by scaling artifacts. Note the jaggies around the red kayak in the water. Hopefully the full resolution version doesn't have those jaggies.</p><div></div>

<p>A number of (mass submission stock) websites will often use blanket technical reasons for rejection because they don't have enough specific reasons. In other words, some of the specific defects pointed out to you by previous respondents will not be as specific by the stock house.</p>

<p>These "questions of rejection" come up all the time in the stock forums.</p>

<p>Are you up-rezzing? (Interpolation) Poor technique in this stage will also cause artifacts.</p>

<p>Thanks guys! A lot of things to think about. I actually shoot in Jpeg so the problem probably comes from there. Gotta start shooting in Raw and see what happens...</p>

<p>Definitely start shooting RAW as soon as you can. Start by experimenting with it on a non-important shoot so you can figure out the workflow in a relaxed situation - not under the crunch of a deadline. It will open up whole new worlds for you once you learn how it works.</p>