May
22
Rethinking our use of US Web Coated (SWOP)!
Filed Under Color Basics, Color Management, Digital Imaging, Herbiology, Images in Print, Memo from the Pressroom
If you are one of the millions of folks who assume that we are producing more accurate files for print today and that Adobe’s CS3’s conversion profiles reflect current printing technologies, you might want to think again.
First, realize that the US Web Coated (SWOP) v2 profile is currently used for most of today’s print projects, regardless of whether the job will be printed on a sheet-fed press or a heat-set web. Second, even if this one overused profile really didmeet the needs of every press technology it still only addresses a single paper white point.
What you should realize is that there are three major press technologies at work daily (non-heat-set web, heat-set web, and sheet-fed offset), supplying the world with printed materials. Each of these press technologies employs a different viscosity (thickness) of ink and therefore deliver different volumes of ink to paper. The ubiquitous Web Coated SWOP profile delivers a single volume of ink (about 300% total area coverage). This starves a sheet-fed press and overpowers non-heat-set capabilities. If you ever wondered why the shadow (darkest tones) areas of your photographs print much darker than you expected or even print thin or flat… lacking the punch and contrast you saw in the proof, you may have already been a victim of this one-size-fits-all assumption.
Over the last decade, both paper and press technologies have improved significantly in the area of quality control, ink holdout and press reproduction consistency. In plain English this means that the printing industry has advanced significantly in these three major areas of technology. By using generic conversion profiles like this guarantees that both image depth and detail will be sacrifice for many projects.
Using the dot gain compensation formulas from a decade ago assumes that the printing industry has stood still while all other technical industries have advanced. This is not only an insult to the industry, it may well be the reason that so many print customers see lackluster printed results from their projects
Perhaps we should consider developing conversion profiles that measure actual press paper whiteness. While this seems to be the norm for ink jet and laser printing technologies, designers are provided only two press profiles (heat-set web and sheet-fed) and only two paper finishes (coated and uncoated) for each. This list doesn’t include the numerous grades (whiteness and ability to absorb ink) and thickness available from most printers. All of these factors influence the way your job will print.
My desktop printer lists profiles for eleven different papers. Eleven!. My CMYK conversion profile choices are limited to four which are proposed to address every printing process and paper, (and we typically use only one)
Houston, we have a problem…
Think about it!
©copyright 2008 Herb Paynter
http://www.imageprep.net
May
21
Gratuitous Technology
Filed Under Color Management, Digital Imaging, Herbiology, Images in Print, Memo from the Pressroom
I was just reflecting on the last decade of technological advancement in the publishing industry and thinking of all that we have accomplished. Let’s review:
Faster computers. Processing speed has increased exponentially. We process enormous-size files in mili-seconds. There are virtually no limits to our ability to push pixels around. I have 4 gigabytes of memory and a 500 gigabyte drive in my laptop and another wireless drive in my house to back up my files every hour while I’m surfing the web from my lanai. I’m writing a book on color reproduction so I’m constantly preparing images and uploading them (wirelessly of course) to my editor in San Jose and my publisher in Indianapolis while I’m video chatting with my sister in Atlanta and listening (with Bluetooth earphones) to a podcast that automatically got downloaded last night.
Higher resolution scanners. Just ten years ago we were pretty proud of the fact that we could capture 300 dpi and 256 levels of color. The flatbed scanners we have now (if we really use them that much) can routinely capture 1800 dpi and 12 bits (4000 levels) per channel.
Smarter cameras. Twelve megapixel cameras are the norm and shooting RAW gives us amazing latitude and versatility with the high-bit color images we capture. With a handful of 4MB memory cards we can shoot with impunity all day long. We can shoot under water and drop our cameras off the roof of our house without fear or damage. We can shoot in near darkness without a tripod, and even shoot hi-def movies if we want.
More powerful software. My CS3 software allows me to work on camera images that automatically get downloaded into Bridge (in RAW format) where they are dutifully opened in Camera Raw where I can do everything to them but make them talk. Eventually I open these files in Photoshop where I build images that have multiple nested layers and special masks and then slide them seamlessly over to InDesign where I build amazingly complex pages. I save selected images for Web use and upload them to my sight (while still on my lanai- yeah, I live there!). I (wirelessly) send images to my perfectly profiled and color corrected ink jet printer where they are printed on double-weight photo paper.
User knowledge. Today’s photographers and designers know more about electronic publishing than ever before. They stay on top of the latest developments and purchase the newest and best of the technology available. It’s safe to say that people in the design world today know more about thier industry than any generation before them. There are seminars and conferences taking place somewhere in the country almost every day of the year.
How come then, with all this advanced technology, we see either a flatline or at best only a marginal increase in reproduction quality in print? Perhaps there is more to this image preparation process than we thought.
Think about it!
©copyright 2008 Herb Paynter
http://www.imageprep.net
Apr
22
Three Dimensions Are Better Than Two
Filed Under Color Basics, Digital Imaging, Herbiology, Illusions, Images in Print
Normally, your eyes don’t see anything in just one dimension. But pictures, whether on a monitor or in print, represent only one view, not two, like your eyes see.
Close one eye and look across the room. Now open it again and see the difference. When your eyes observe a scene, your brain merges two slightly different views of a scene (one from each eye) building a third dimension, depth, into your mind.
This phenomenon of depth perception can be crudely simulated by such things as 3-D movies, where two opposing colored lenses (usually red and green) recognize slightly misregistered (green and red) images recorded from two cameras lined-up at about the same distance apart as the human eyes. The red image is cancelled-out by the red lens and the green image is cancelled-out by the green lens. Once again, your brain is called on to assimilate two images into a single scene. Your brain is very tolerant of human silliness.
But in the case of printed images, your mind excuses single-vantage-point images, allowing you to perceptually accept the image as real even though your eyes have never actually seen such a thing in real life.
Think about it!
©copyright 2008 Herb Paynter
http://www.imageprep.net
Mar
31
Dynamic Range: Newspaper
Filed Under Color Management, Digital Imaging, Herbiology, Memo from the Pressroom
In case you hadn’t noticed, printing images in the newspaper is an abysmal undertaking. While pretty much everyone knows that this morning’s newspaper is tonight’s birdcage liner, few people truly understand the stark reality of newsprint’s (lack of) dynamic range let alone what to do about it. Illustrated here is a sobering reminder.
The four gray squares you see are actual colorimeter measurements (converted to grayscale format) of two different newspaper publishers’ paper and solid black ink colors. Here’s the unvarnished reason that pictures in the newspaper need special preparation. The two squares on the left show the solid black ink density measurement and (on the right) the unprinted paper “color” measurements taken from a (typical) daily newspaper and the same measurements taken from USA Today. While USA’s “black” is darker and the paper whiter than the daily newspaper, both show the extremely shallow dynamic range available in newsprint in general.
THEREFORE, pictures prepared in a typical Photoshop fix-em-up fashion (as if to be printed on an ink jet printer or even a glossy publication) will print horribly on newsprint. Images destined for the newspaper (whether black and white or color) MUST be prepared specifically (never using the ubiquitous US Web Coated SWOP v2 conversion profile) for this tonal range in order to reproduce well. To achieve the correct tonal balance, unique mid tone, highlight, and shadow adjustments are required.
If you are not familiar with either this issue or how to deal with it, let me know. There are answers.
Think about it!
©2008 imageprep.net
hfp@imageprep.net
www.imageprep.net
Mar
24
Multiple Black Inks- No New Thing
Filed Under Digital Imaging, Herbiology, Images in Print, Memo from the Pressroom
One of those (not so new) great thing about today’s ink jet printers, both large and small, is that they print really great black and white prints. And the way they can do that is by extending the range of the tones by using two different black inks; or to put it more accurately, a black and a gray ink. The best of the photographic ink jets actually use three different shades of black/gray inks.
While this is admittedly a brilliant methodology, it hardly a new technological breakthrough. Not the groundbreaking discovery it might seem anyhow. How do you suppose those great looking Ansel Adams limited edition lithos were produced?
The process is one that has been routinely used in the printing industry for at least 35 years, maybe more.
The technique is referred to as duo-black in some parts of the country and black/gray duotone in other parts. To produce this effect the litho cameraman produces two different halftone negatives from a single photographic print. One halftone is shot to represent the shadow-to-mid range of tones and the other to cover the middle tones and highlights. These halftones produce two different plates which are then mounted on two different units of a multi-color press. Halftone black ink (a translucent black ink used in four-color printing) is put in the unit with the shadow plate and gray ink is put in the highlight unit. When combined, these inks produce a terrific deep, rich, extended-range black and white print.
Surprised? Don’t be. It’s just another science borrowed from the printing trade that has blessed today’s digital market.
You’re welcome, desktoppers!
Think about it!
©copyright 2008 Herb Paynter
http://www.imageprep.net
Mar
16
Ink Jets Versus Printing Press- Reality Check
Filed Under Digital Imaging, Herbiology, Illusions, Images in Print
I’m writing a book called “Correct Color” for a major publisher. It is a guide to achieving accurate color in printed digital images. In the process of “due-ing the diligence” thing and researching existing published materials for the project I read a significant number of other peoples’ books on similar topics.
While I always learn new things from these works, It never ceases to amaze (and amuse) me just how many of the Photoshop/Camera Raw/Lightroom books contain the same apology for their printed illustrations. The typical disclaimer goes something like this… “I will enlarge this part of the image 200% to let you see the adjustment detail we are making because at actual print size, the adjustment won’t show in print.”
“Hello!! Is anybody listening to this silliness?
If the particular adjustment procedure being taught cannot be seen in print without being enlarged to an overtly-extreme level, then is that adjustment actually meaningful? Is it necessary to enlarge the view to such an enormous level to see an adjustment being made? Does the adjustment need to be made if the results can’t be seen in print? (rhetorical question)
If we can’t see it in print then perhaps the adjustment is overkill. While it may be true that high-level ink jet printers can reproduce and delineate more detail than can a printing presses (running reasonably-high lpi screens), it would seem reasonable that those books teaching minute ink-jet-only adjustments should be produced on the same inkjet printers for which the adjustments apply. More accurate assertion: since the overwhelming majority of all images are printed on real printing presses, perhaps more press-related image-adjustment issues should be taught in these books. Then the illustrations could be produced in real-time (100%) size and deliver their message with great applicability and validity. What a concept!
Think about it!
©copyright 2008 Herb Paynter
http://www.imageprep.net
Great care should be taken when boosting saturation in a digital image simply because there is a thin line between optimal saturation and luminance damage. Photographic saturation has a scientific definition and a practical definition. I believe we need to recognize both in order to really grasp the issue.
Photographic saturation is basically color intensity, expressed as the degree to which it differs from white. Get the picture? It’s what differentiates a grayscale image from a color image. A color image without saturation is just luminance. Now mix this with the white-bread definition of saturation: the state when no more of something can be added. Combining these two definitions actually provides a very practical guideline to the use of saturation in digital imaging. It’s called “too much of even a good thing is still too much!”
Open up an image in Photoshop and pull up the Hue/Saturation dialog box. Now slide the Saturation triangle all the way to the left. See what you have left? A grayscale (what we use to call black and white) image… all form and no color. Now slide the triangle back through the middle and all the way to the right side of the scale. Now (after you pull your eyeballs out of the back of your head) you’ll notice that the image is now pretty much destroyed… all color and no form.
We all enjoy very colorful things. God gave us an imagination that is very rich and colorful. And frankly, sometimes digital photos need a little more color. But take great care in the exercise of your imagination as it can push your pictures beyond “believable.” Here’s how to how to maintain the “best” of a good thing. Go back to the Hue/Saturation adjustment dialog and carefully slide the Saturation triangle to the right but stop short of losing any of the highlight tonal definition. You can also balance more Saturation with less of the Lightness channel (unless the picture gets too dark)
Think about it!
©copyright 2008 Herb Paynter
http://www.imageprep.net
Mar
12
Higher-Bit Images Don’t Increase Dynamic Range
Filed Under Color Basics, Digital Imaging, Herbiology
By now we all know that 8-bit images contain 256 levels of color spanning from solid to no color at all. And if we do the math (2×2x2×2x2×2, etcetera, ad nauseum) we see that higher bit-depths deliver exponentially-higher amounts of tone between solid color and no color. 9-bit images contain 512 levels, 10-bit contain 1024, and so forth. All those teeny-weeny steps just get smaller and smaller the higher up the bit-ladder we travel. All well and good.
But do you realize that for all that frothing about levels of tone absolutely nothing changes concerning the bookend colors themselves? Let me state this a little differently. Let’s start with an 8-bit RGB image that doesn’t have a great range at all. Perhaps it’s darkest color is R25G57B31 and its lightest color is R230G228B211. The dynamic range of this image is relatively low. In grayscale values that’s about 88% dark to 13% light.
Guess what happens to that shallow range when we move from 8-bits per channel mode all the way up to 16-bits per channel? Absolutely nothing! We’re still stuck with a contrast range that delivers all the excitement of a bowl of oatmeal. WOW! Think of the quality edge we just purchased with all that hard disk real estate.
OK, enough with the sarcastic talk. But do consider this…
The visual dynamic range limitations of any printing device (combined black ink density versus paper white) determine the appearance of any image sent through it. Here’s a fact to consider. The dynamic range of any printer is less than that of a glossy photographic print… 1.5:1. And simple truth is that little more than 200 levels of tone can be discerned by the human eye. Do some checking into this before you spend oodles of time adjusting for minute detail in high-bit mode.
Think about it!
©copyright 2008 Herb Paynter
http://www.imageprep.net
Mar
11
Unsharp Masking Origin
Filed Under Color Management, Digital Imaging, Herbiology, Images in Print
What does unsharp masking have to do with image sharpening? Well… very little in one respect, but a lot quite a lot in another. The term originates from a very unlikely source. Check it out—
In the lithographic pre-digital world of color separations, continuous tone CMY negatives were produced by placing red (#25), blue (#47B), and green (#58) Wratten filters in front of a process camera lens as individual CT films were exposed, one at a time, from a single color picture. Typically, the resulting CMY color negatives contained way too much contrast for the halftone contact screens used to transpose optical information into halftone dots. When too much contrast was delivered to these contact screens, they failed to faithfully deliver the full range of tones, rendering highlights blown out or shadows plugged.
To remedy this situation it was necessary to reduce the contrast of the separation films. This contrast reduction was accomplished by producing shallow, soft-focused film positive masks from the CMY negatives. The masks were generated by placing raw continuous-tone film on registration pins in a vacuum frame, placing a sheet of frosted acetate on top of the raw film, and then mounting one of the color negatives on top of the acetate. This film sandwich was drawn down under significant pressure and exposed via a carefully-controlled pin light source,
The net result of this “unsharp mask” procedure indeed reduced the overall contrast of each of the cyan, magenta, and yellow separation films. The resulting corrected contrast range enabled each of the color negatives to produce full range tonality. Interestingly, the byproduct of this process provided an additional benefit to the image quality. The soft nature of the positive mask sandwiched against the crisp edges of the original negatives produced a natural edge emphasis on all contrasting areas of the films. This emphasis delivered the net optical effect of detail sharpening. Now you know the truth about USM and what old-school litho gave to the new digital imaging movement!
Think about it!
©copyright 2008 Herb Paynter
http://www.imageprep.net
Mar
8
Different Presses Have Different Appetites
Filed Under Color Management, Images in Print, Memo from the Pressroom
Not all printing presses operate the same. There are many different printing processes, each requiring a unique machine, and each transferring ink onto paper in a unique manor. Therefore, for best results, each of these presses deserve unique file preparation (profile conversion) to produce their best results. Press speed, paper quality, and ink viscosity play major roles in determining the best halftone screen structure. And this halftone structure must address each press’ appetite.
Printing inks used by a high-speed web press are the consistency of light syrup while sheet fed press inks are more the consistency of peanut butter. In addition, there are papers of every grade, brightness, and color (white point) that are routinely used for different projects. Each ink formulation and paper type require a different screen frequency and each screen frequency delivers different dot gain amounts. Get the picture? Variety is the name of the litho game. No one “profile” conversion can meet all the varied needs of the printing industry.
Here’s a couple of illustrations…While an automobile-size engine works fine for an automobile, it is woefully inadequate to power a trailer truck and yet tremendously overpowering for a go-cart. While all three vehicles are powered by engines, no one engine is appropriate for all vehicles. Now consider this… while all machines require oils to lubricate internal moving parts, smaller machines require much thinner viscosity oils. Motor oil would gum-up a sewing machine and sewing machine oil would fry an automobile engine.
Principle learned: One size does not fit all! And this principle certainly applies to printing presses. Only heat-set web presses printing coated stock should be fed US Coated SWOP v2 separations. If you are preparing all printing projects using the same recipe instead of treating each project individually, you are definitely short-changing yourself on print quality.
Think about it!
©copyright 2008 Herb Paynter
http://www.imageprep.net