Friday, March 22, 2013

The Color Modes: Grayscale


This is the second in a series of posts discussing the color modes in Adobe Photoshop. One of my previous posts, ‘256 Shades of Gray: A Ribald Tale of Bit Depth’ covered the color modes available in Photoshop when starting a new document. This series of postings will go into each one of those modes in a little more depth plus cover the other secondary color modes. My goal is to keep things simple in this blog. So I won’t be going into much depth with bit-depth. I’l just go a little bit…in depth.

The Grayscale Color Mode in Adobe Photoshop



When you are only printing one solid color, but want tints or screens of that color. The color can be black, white or any single ink or spot color. But check with your print vendor to see how they handle whites. Not all printers are equal when it comes to printing white.

The Grayscale color mode in Photoshop is pretty much the same as the Bitmap mode, but with the ability to tint your single color with varying percentages or levels.

When starting a Grayscale file you have the option to choose 8-bit, 16-bit or 32-bit.
Which ‘bit’ option should you choose? Well the standard is 8-bit. 8-bit is universal when it comes to which print vendors and which equipment can handle that level of print quality.

8-bit will give you 256 shades of gray…if you count black and white in with that 256. 16-bit will give you 65,536 shades of gray and 32-bit…will give you a whole bunch more. When it really comes down to it, who needs to know a number? Essentially, the higher the bit depth - the more colors you have, meaning gradations looks better and colors have the potential of being more varied and vibrant.

32-bit and higher should only be consider for HDR or High Dynamic Range images. This is most thought of for use in color images but can benefit grayscale as well by offering more steps between you typical darks, mediums and brights.

Consider using 32-bit Grayscale if you are planning on printing an image with a single spot color. You could create or retouch an image in 32-bit, then assign a single spot color ink instead of black ink to see if the image pops more. You could also create or retouch the 32-bit Grayscale image to your liking, then duplicate the one grayscale channel to four separate channels or plates printing in CMYK to create a dynamic effect.

Grayscale comes in handy when you are creating a line of packaging that may have a number of variants with a common image, but with a different variant spot color on each package, label or wrap. Use the same grayscale image for each, but assign the different spot color for each package when sending out the final art.

It comes down to knowing who is printing your job and what their capabilities are. If we are strictly talking about ‘on-screen’ viewing - all bets are off and you can do whatever the quality of the viewers monitor can handle.

For the most part, you should stick to 8-bit for your Grayscale, but experiment with higher bit depths and research HDR for higher end photography and retouching.


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