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Message: <blockquote data-quote="WayneF" data-source="post: 325166" data-attributes="member: 12496">Clipping is the single most important factor about monitoring exposure (because it cannot be corrected).  Clipping just means overexposure, but in a specific most-harmful way:Adding additional exposure (in camera, or with ACR Exposure slider) moves the histogram data right (brighter).When the right end of the data reaches the right end of the histogram, it can go no farther, there is nothing beyond 255 (8 bit numbers can only range from 0 to 255... 8 bits can count no higher, 256 requires a 9 bit number, which JPG does not have).  So the right end just hangs there clipped at 255. Additional exposure just piles up more pixels, clipped at this right end at 255, and we see a tall spike develop in the histogram data right on the 255 end.  That spike denotes clipping (data piled up at the 255 end).We can have overexposure (say of dark colors) that does not reach 255, and this can be backed off and corrected.  No actual problem, at least not in Raw.  In fact, some intentionally do this, and call it Expose To The Right, as a way to reduce digital noise.  When we shift the data back down, we shift the noise down too.But if clipped at 255, it cannot be corrected or restored, that data is gone (clipped, converted to 255 when it should be higher).  Mild cases probably only clip one of the RGB channels, but this still changes color, the colors are not what they should be.You can see this happen in ACR, in a test, just boost exposure too much with the Exposure slider, more than enough to reach the right end.   (I should shout IMPORTANT here... <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite1" alt=":)" title="Smile    :)" loading="lazy" data-shortname=":)" />  )   When there is actual concern, in ACR, you can see which pixels are clipped or clipping, by holding the keyboard ALT key, and touching and holding the ACR Exposure slider with the mouse, and the screen image turns black, except for the pixels that are clipped. As you move the slider, you see more pixels be clipped.    Adobe Levels works the same way.  Now you know what is clipped, or what you are clipping. If this test case clipping is something like a human face portrait, probably the face suffers early clipping.  The skin color becomes white and pasty color, with no detail in it.But there are don't care cases when a little clipping may not always matter (in unimportant image areas, maybe a glare on a table surface), and benign clipping is one way to increase brightness and/or contrast (there are better ways).We cannot restore clipped data in the original image (if it is clipped and gone), so it is important to monitor this histogram in the camera, at the scene at the time, when it can still be corrected and repeated.      It merely takes a glance.   The camera shows one single gray histogram, which is useless to show clipping.  It also shows three RGB channels, which is where it's at.  If any of the three RGB channels show clipping (the spike touching the right end), back off on camera exposure.  Red flowers in sunlight typically clip a little in the red channel.Here is an example of that:    <a href="http://www.scantips.com/lights/histograms.html" target="_blank">Two types of Histograms</a> Your diffusion screens sound like a good thing. I guessed maybe Win7 and Win8 can use the same driver?    I don't know about Spyder4, but would not expect that compatibility.  I don't know the difference, but the cost of the new one is not extreme.  I just use the old one because it performs very well.IMO, there is not a big difference, but there is a difference, and calibrated is better.  LCD monitors are normally too bright for photos, and calibrating can bring that back down, so the images you adjust will look better elsewhere.  I also set the cameras LCD Brightness to -1, to make it better match the computer monitor.</blockquote>

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