Ever ask yourself what do the numbers mean when post Processing in, Adobe Camera Raw, Photoshop or Lightroom? If you haven’t you should as they are very helpful at letting you know how your final image will reproduce or look to the viewer. There are a few important things the numbers tell us among them are the white and black points where detail is lost and how neutral or color balanced your image is. Just to complicate things a little Lightroom uses a scale of 0 to 100 while the RGB space in Adobe Camera Raw and Photoshop use 0 to 255. If you are going to print the numbers in the CYMK color space uses 0 to 255 but do to the print inks not being equal the color balance, white and black points are totally different than any other space. I will write at a later date more complete information on color balance in the CYMK space.
I have done post processing under some terribly poor conditions doing prepress work. Bad lighting, bad monitor and no way to proof my work but all was fine in the end because the numbers never lied. One time I had a dark, and I mean dark green chair that printed neutral black. Well it turned out the printer thought that I let the yellow go a little two high so he color corrected the image. Yellow might get you confused if you don’t know the CYMK color space but when yellow a very strong color goes up the blacks go green.
The endpoints of an image are the points where detail is lost in the blacks and the whites. Most indicators in our programs show the limits of the color space which is way past where detail is lost.
Below is a chart showing the 95%, 50%, 10% and 5% points and a 100% and 0% reference bar. The 95% point is where detail is lost in any higher value. The 50% point is for your reference and the 5% point is the point of last detail any darker you will have no detail. Next the 10% point will look lighter on a screen as it is backlit and in real life if the image is printed this is a better selection as your black point. The misunderstanding of this fact is one of the reasons prints seem to be darker than on your screen. Your printer works from the numbers and the numbers don’t lie. If your print is too dark increase the contrast in the dark area and raise the values.
This chart was put together in Photoshop using the Pro Photo profile and converted to sRGB for screen display. The numbers in the sRGB file are slightly different as Pro Photo profile is much larger and so things a squeezed a little to fit into the smaller sRGB space. How this chance occurs is controlled by the rendering intent of your color setup. I use relative colorimetric which is best for prepress and works very good in other situations. The Perceptual rendering intent is also workable and I do softproof using both but most the time choose Relative Colorimetric. The numbers in lightroom will differ and the numbering scale is not linear. So after completing the above file I measured the Lightroom numbers to be the same as the file converted to sRGB even though my Lightroom is set up for Pro Photo.
Lightroom is very visual in the way it works and it seems to display things as they will appear on a screen in sRGB so it is important to know the numbers. The end point for White is 96.2 and 5% Black is 5.9 with printable detail 10% black is13%. Middle grey is 57.4 percent. These numbers are the same for sRGB files and should be the numbers used in Lightroom even though you work in another color space inside lightroom. This is not bad because most screens are built to cover the sRGB space so you are working with the numbers that work for a vast amount of people.
I am hoping this blog works well for you and welcome any feedback or questions. Do not forget to subscribe so you wont miss the next blog. Until next time “Keep on Shooting”.