Why increase moiré in Lightroom?

[Kent Shafer]

<p>Lightroom 4's adjustment brush has a moiré slider that goes from -100 (reducing moiré, which is good) to +100. The default is 0. Why would anyone want to increase moiré?</p>

[rodeo_joe1]

<p>Kent, are you sure that the zero position does nothing? It seems more likely to me that the "0" setting represents an average moiré reduction, and that the +100 setting is the one that does nothing. Or maybe it's just a detail sharpness slider by another name, where +100 sharpens detail and so would tend to aggravate the appearance of moiré. Who knows what runs through the minds of Adobe's programmers?</p>

<p>BTW, I can't believe how quickly "moiré" has become such a talked-about bogey since the introduction of the D800E. If it's such a bad thing, why the heck are people buying a camera that'll encourage it? And paying extra for the privilege?</p>

[patricklavoie]

<p>Kent, its a good question.. dont think of anyone really wanting to put more moiré.. since i dont have moiré problem i cant really test it, but theres should be a why you can put this slider to the + slide.</p>

<p>portrait/fashion/studio/architectural/bird photographer, then get the <a title="Nikon D800" href="http://mansurovs.com/go/bh/nikon-d800">Nikon D800</a> – you would be better off with an AA filter. If you are a landscape or a macro photographer, then you should get the <a title="Nikon D800E" href="http://mansurovs.com/go/bh/nikon-d800e">Nikon D800E</a> to get the maximum detail out of the high-quality 36.3 MP sensor.</p>

[phule]

<p>One thought: If the camera has some anti-moire setting that is user-configurable (and part of the RAW metadata read by Lightroom), but you found the softening too aggressive, then you could dial it back with the + side of the slider.</p>

[patricklavoie]

<p>Not sure that exist? i normally reduce morié via C1Pro (when shoothing with P45 or IQ60-80).. less of a problem with regular dslr like MArkII - III.. maybe your right Rob?</p>

[Kent Shafer]

<p>Rodeo Joe, that's an interesting idea, though it seems odd that Lightroom would apply moiré reduction all over every image by default and not provide any way to eliminate it on a global basis.</p>

<p>I'm not aware of any moiré setting in the camera (a D800E as some of you correctly assumed). There's no listing for it in the user manual's index.</p>

<p>If I had to guess, it would be that the programmers did it that way just because they could (that whatever the algorithm for moiré reduction is, the math can work in reverse) and because it made that slider symmetrical with the others.</p>

<p>(The interest in this subject is at least helping some of us English speakers learn to type the "é" character.)</p>

[rodeo_joe1]

<p>Only because it automatically comes up with [Alt Gr] + E. If it was any more difficult than that I wouldn't bother. ;-)</p>

[sheldonnalos]

<p>I tried the Moire Adjustment tool on a shot with moire (taken with a MFDB with no AA filter). From what I can tell, there is no effect on Moire for settings between -100 and 0. As you move the slider towards +100, the moire reduction effect becomes stronger. Think of it as "turning up" the moire reduction. </p>

[mark_sirota1]

<p>Negative moiré in a brush is useful to offset the effect of another brush.</p>

[Kent Shafer]

<p>Thank you all for your helpful responses. I clearly still have a lot to learn about this.</p>

<p>I'm now starting to think that the image I was looking at (a test chart, of all things) isn't exhibiting moiré at all but something else instead. To me, the fine vertical lines appear in various colors even though they're all actually black. Maybe this is chromatic aberration or even some physiological phenomenon having to do with how the human eye works. (Or maybe just my eyes.)</p>

<p>Even if this image isn't displaying moiré, I'll undoubtedly run into it sooner or later and will be glad to have the insights you all have provided.</p>

<p>Anyway, here are three versions of a 100% crop from the test chart image, with +100, 0, and -100 moiré correction respectively. To be honest, I can't see any difference.</p><div></div>

[Kent Shafer]

<p>Well, this is interesting. Here's the same image but with extreme boosts to contrast and saturation added in Photoshop. This seems to show that Sheldon is correct: negative moiré correction doesn't do anything, but positive does.</p><div></div>

[Kent Shafer]

<p>OK, this is the last thing I'll post on this subject unless someone else is interested in continuing the discussion. It turns out that the test chart image does exhibit moiré, but it's fairly subtle. I have learned the following from this exercise:</p>

<ul>

<li>Boosting saturation but reducing contrast (not increasing it as in my previous post) makes moiré more apparent. In the image below, the effect is particularly visisble in the two finest groups of diagonal lines on the top left. When attempting to find and correct moiré in Lightroom, it will probably be helpful to first temporarily increase saturation and reduce contrast for the image as a whole.<br /><br /></li>

<li>Lightoom's tool, used with positive values, does a pretty good job of correcting moiré. Negative correction doesn't seem to do much of anything, though looking at the image below I can sometimes convince myself that the moiré is slightly more pronounced in the -100 area. Or maybe not. <br /><br /></li>

<li>Though not directly related to the OP, I found that sending these test chart images to an Epson 3800 printer at oddball resolutions resulted in obvious interference effects in areas with fine details. These effects (also a species of moiré I suppose) were not visible on the computer screen—they were generated entirely in the printing process. Up-rez'ing (never sure how to spell that) to 360 ppi completely cured this issue. I tried both Bicubic and Bicubic Smoother. Both worked, and if there's a difference, I'm not able to see it.</li>

</ul><div></div>