![\"8](\"https:\/\/valleau.art\/blog\/wp-content\/uploads\/2021\/10\/8-vs-16-print-1.jpg\" "\\"8")
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So, you’ve just spent hours, maybe days, working on an image, carefully using a 16-bit depth, to keep the colors perfect and the tones smooth. The sky will be perfect printed at 2880, and the clouds sublime.<\/p>\n
You save the file as 16-bit tif, and send it off to the printer. And it is indeed lovely! Congratulations!<\/p>\n
… but something is not quit right. The tones are not perfectly smooth and the shadow just look odd, at least seen from some angles.<\/p>\n
You look closely and see very subtle banding. Whoa! What’s this???<\/p>\n
The quick answer: it’s an 8-bit print, not a 16-bit print.<\/p>\n
Here’s how to see the effect yourself, and how to tell if your printer is actually getting 16-bit images.<\/p>\n
Let’s run this experiment:<\/p>\n
Open Photoshop.<\/p>\n
Create a new image 4000 pixels wide and 1000 pixels tall and be sure it’s set to white background and 8-bit RGB.<\/p>\n
Select the gradient tool with B&W and while holding down the shift key, drag a gradient across the full width of the canvas.<\/p>\n
Save the image as “8-bit” and JPEG, maximum quality.<\/p>\n
Now do the same thing all over again, and again make the image 4000 px wide but this time, make it 2000 pixels tall.<\/p>\n
Also different: this time be sure to set it for 16-bit instead of 8.<\/p>\n
Drag out the gradient again.<\/p>\n
NOW, drag the 8-bit image you created first on to the open 16-bit image. (This places the smaller 8-bit image on top of the larger 16-bit, right in the center.<\/p>\n
Flatten the image (using the layers menu).<\/p>\n
Save the image file as a TIFF, 16-bit, uncompressed. I suggest naming it “8 & 16 bit”.<\/p>\n
Now it’s time to use it.<\/p>\n
First, open the Photoshop info window, and set the RGB readout value to 16 bit, actual color.<\/p>\n
Then zoom in to about 3200- 6400 percent, so that each pixel is about 1\/2″ size on your screen.<\/p>\n
If you followed the instructions above, the center 50% of your image will be at 8-bit depth, and the top\/bottom 25% will be at 16-bit depth.<\/p>\n
Scroll to the top or bottom, and watch the info window 16-bit readout as you scan the cursor across the width of the image. You will see a different value for every single pixel\/column you scan across.<\/p>\n
Now, if you scroll to the middle of the image, and repeat the process, you’ll see that you have to cross about a dozen different pixels before the 16-bit number changes.<\/p>\n
That’s because there are only 256 levels across the whole image in 8-bit mode, so a column of several pixels wide will have the same value. (ie 15 columns at 121, then 15 columns at 122, and so on.)<\/p>\n
(Depending on the quality and calibration of your monitor, you -may- be able to see the faint banding in the central 8-bit section.)<\/p>\n
Finally, you can use that same saved “8 & 16 bit” tif file to check your printer. You can see the effect in a printed image, -and- you can see if your printer really printed using 16-bits.<\/p>\n
Print the image at highest resolution on a RC paper. If the file was sent at 16-bits, you’ll see the vertical banding in the center of the image, where the 8-bit section is, and no banding at the top and bottom 25%.<\/p>\n
If you see the banding, but it’s across the entire image, from top to bottom, then your image was automatically converted to 8-bit by the software you used to print it (such as Qimage, or anything else that uses Apple’s internal vImage API.)<\/p>\n
In the example image below, I have enhanced the effect to make it visible online. In an actual 16-bit print the effect is much more subtle. The point however, is that it IS noticeable, usually in areas of near-flat tones, such as sky or shadows.<\/p>\n
If you have seen this in your own prints, now you know why: it’s being printed as an 8-bit image.<\/p>\n
hth<\/p>\n
<\/p>\n","protected":false},"excerpt":{"rendered":"
\u00a0 So, you’ve just spent hours, maybe days, working on an image, carefully using a 16-bit depth, to keep the colors perfect and the tones smooth. The sky will be perfect printed at 2880, and the clouds sublime. You save the file as 16-bit tif, and send it off to the printer. And it is […]<\/p>\n","protected":false},"author":2,"featured_media":445,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"class_list":["post-446","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-photo"],"_links":{"self":[{"href":"https:\/\/valleau.art\/blog\/wp-json\/wp\/v2\/posts\/446","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/valleau.art\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/valleau.art\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/valleau.art\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/valleau.art\/blog\/wp-json\/wp\/v2\/comments?post=446"}],"version-history":[{"count":2,"href":"https:\/\/valleau.art\/blog\/wp-json\/wp\/v2\/posts\/446\/revisions"}],"predecessor-version":[{"id":449,"href":"https:\/\/valleau.art\/blog\/wp-json\/wp\/v2\/posts\/446\/revisions\/449"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/valleau.art\/blog\/wp-json\/wp\/v2\/media\/445"}],"wp:attachment":[{"href":"https:\/\/valleau.art\/blog\/wp-json\/wp\/v2\/media?parent=446"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/valleau.art\/blog\/wp-json\/wp\/v2\/categories?post=446"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/valleau.art\/blog\/wp-json\/wp\/v2\/tags?post=446"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}