MonthAugust 2016

Why Resolution & File Formats Matter

Image Resolution and file size

Resolution is worth mentioning because it causes so many problems in the prepress department. Any image you want to print must be a minimum of 300 PPI at 100% of its actual size. If you pull an image from a website, and it is 4 in. x 4 in. and 72 PPI (the typical web resolution), when you place it in your page layout, it must be sized to 24% of its original size or .96 in. x .96 in. in order to be at the correct resolution for printing.

There is absolutely no way to take a low-resolution image and make it look like a high-resolution image. Interpolating a file to a higher resolution makes the image look like an image that was interpolated up to a higher resolution to improve its appearance. One low-resolution image can make a whole brochure look cheap. Make sure all the images you provide are the correct resolution for their output size.

Here I have pasted three different file sizes of the same image. I adjusted their dimensions so they would each be about the same size “on this page”. Below each fish pic is the Adobe Photoshop screenshot showing the image “dimensions” in pixels and inches.

fish tinycomparison

1x.79

 

fish comparison4x3_72

 

fish 9x6comparison

fish9x6
You can decide for yourself which image looks best. On the web it is not necessarily about looks, there is also the loading time and the number of colors used to display the image. That will be covered in a later post.Below are the same three photographs, all placed at the same size into an InDesign document. Then I exported the document as a jpeg at a screen resolution of 72 PPI. By building this image in InDesign I am able to show you how a low-res file that looks bad on the screen will look like that in print.

fish comparisonlow

 

Specify and use correct file formats

Each software program creates a native file format that it “gets along with” best. For Adobe Photoshop, that would be bit-mapped files like TIFF, JPG, and PNG. For Adobe Illustrator, it is EPS files. Adobe InDesign is a composition program that can accept nearly any file type for inclusion into a document that will be printed or published to the web.

Some file formats work well for print, and some work best for the web. Here are some common file types and their best uses:

Print

  • TIFF: for high-resolution photographs and scanned graphics
  • EPS: for infinite scalability
  • PDF: for high-resolution printing when properly saved with embedded fonts and bleeds, etc.

Web

  • JPG: for many compression options and fast loading
  • PNG: for more image depth. The trade-off is its large file size, no CMYK: RGB only.
  • GIF: limited color (256 only) but very fast loading

Don’t use image compression unless you absolutely have to. Every time an image is compressed (when it is saved) and uncompressed (when it is opened), it rewrites the data in the file and leaves little artifacts/noise in the image.

Compression is left over from the days when a 44 MB (yes, that’s MB, not GB or TB) Syquest drive cost $200. Nowadays, storage is cheap. Compression works well for the web, but it isn’t necessary for anything else. For example, Tiff files and images are not compressed. Jpeg files and images are. Here is an example of how to save a TIFF image without compression.

tiffnocompress

If you have had an experience with resolution or file types that you found helpful, or from which you learned, please share it below. Thanks!

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Designing for Digital Printing

Designing for digital printing is similar to designing for offset printing. The disadvantages of digital printing (compared to offset) can be handled easily in the design stage. And the advantages you can plan into your design from the beginning, isn’t that easy and awesome?!

Advantages of digital printing

  • Short-run—No minimums! You can just order one and you may be surprised to know that digital printing can be cost-effective for a quantity up to 5,000 depending on the size of the finished piece and the number of inks needed.
  • Less paper color shift—Digital press inks are more opaque resulting in more accurate CMYK approximation of spot colors and less of a shift on colored stock. A 100% black looks like rich black because DMAX percentages do not apply to laser builds. (more about that tech stuff in another post)
  • Versioning and personalization—Versioning uses variable data to customize the printed item for the recipient. For example, a brochure mailed to a woman might feature a photograph of a woman on the front, while the same brochure sent to a man might feature a photograph of a man. Personalizing can be more than simply inserting the recipient’s name in a letter. It can also be about telling Suzie that her particular make of car is due for service or sending a letter to Frank with a personalized message that his heating system is due for duct cleaning. If you are thinking of customers that would love to have these features into their marketing campaign, but you and they do not have the database expertise, don’t worry. All you need to do is look for a printer that does mailing and they will help you integrate your clients’ marketing with versioning and personalization.

IMG_1613

Some digital presses can print on transparent media and even lay down white ink, now that’s incredible!

Digital printing also has disadvantages:

  • Small type may look messy, especially if it is in color
  • Solid areas looking blotchy, there are some workarounds we will discuss later.
  • Not all printing papers will work. Metallic papers, super thick papers, it depends on what kind of press your printer is using.
  • Difficult, if not impossible to apply finishing processes that require exact registration, such as foiling or embossing and coatings such as varnishes or AQ.
  • Don’t expect match color from one print run to the next.

The majority of digital presses are toner/dry ink based, but also include liquid ink digital presses. Large-format digital printing, which is only inkjet (i.e., liquid ink), will be described in a separate post.

Things to do for a digitally printed project:

  • If you have small type in color, make one color at least 100% (the same as for offset printing).
  • When knocking-out type from a background that has a screen build of multiple CMYK colors, make sure that the screen build has at least one color that is set to 100%. This helps the type look cleaner.
  • Minimum 1200 dpi for line art.
  • If you use a large solid-colored or tinted area in the design, ask for a sample or test from your printer. If you are not 100% happy with how the sample looks, get suggestions from your print provider on what technique will work best to achieve the look you want. Sometimes changing the screen percentage or adding a texture can improve the appearance of the solid or tint.
  • Know the size limitations of your print provider’s equipment before you start designing, especially if your job involves scoring.
  • When building a gradient to create a gradual transition of color, for example from black to white, set the “white” part to 0% black, not white.
  • Check with your vendor before including metallic paper, or imprinting a shell with a metallic ink, or foil stamping, in a digital project. Most digital presses cannot print on metallic paper or imprint on paper that has a metallic foil-stamped element in place.

Don’ts:

  • Do not use type below 8pt in the file.
  • Do not apply a color to type that has less than 100% of one color, e.g. 80% cyan or 40% yellow.
  • Do not have large areas of solid color unless at least one of the colors is 100%, and even then that could be risky.
  • Do not build rich black in your file if you want a rich black. 100% black is the densest, darkest black on a digital press. If you want a black that shifts to red or green, for example, then use a CMYK formula.
  • Do not have large areas of tint color. If you do, then you can expect banding, splotching, and general unevenness.
  • Make sure that any lines/rules are set to an actual width and not “hairline.” Avoid rules under .25pt.
  • Do not convert RGB (Red, Green, Blue) images to CMYK. The look-up tables in your print provider’s RIP are specifically designed for their digital inks and their particular digital press.  Do not use the look-up tables in Photoshop or InDesign, which are designed for lithography inks.
  • Do not place a score through an area of solid ink coverage. Dry ink or toner is especially brittle and difficult to fold without cracking.
  • Do not use a digital shell for imprinting in laser printers—unless the digital shell was printed on a laser-compatible device. The output from some digital presses will smear in a laser printer.
  • Do not specify a Pantone color in your file unless the following occurs:
    A. Your print provider has digital equipment that can use a spot ink/toner (this is uncommon, and there may be a hefty surcharge to get a digital PMS on your job).
    B. Specify a Pantone color with the knowledge that it will be converted to CMYK or CMYK plus additional hifi colors such as orange or green, and let your print provider’s rip do the conversion; its look-up tables are superior to what you would specify from a Pantone selector or library because they are designed for the press manufacturer’s inks/toners. If you have a client with a substantial amount of digital printing and the branding includes a tricky Pantone color, ask your print provider to work with you on specifying a digital CMYK equivalent that your client will be happy with. This might involve some extra tests but is worth it in the long run.
  • Some digital presses that are dry ink or toner-based leave a film over the entire sheet that is very difficult to write on with pencil or pen making it impossible to use for forms that need to be filled out manually, and labels or adhesive may not stick.
  • Do not include die-cutting, embossing, or foiling in a design that will be digitally printed.

digital test

This image shows the same page printed on two different digital presses. In the center is the Pantone Bridge selector showing the PMS and CMYK equivalents for PMS 647. It’s difficult to make this really clear online… but you can see that the print on the right is slightly more red in both the solids and screen tints. The page on the left rendered the solids and screen tints ever-so-slightly less smoothly than the page on the right. There are slight differences as well in the way the type was imaged on both pages. The moral of the story is, today’s digital presses are all very, very capable presses. They are designed to have different strengths than sheetfed presses.

Comment below with digital printing surprises you have experienced. I would love to hear about them!

Confused about digital printing?

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Choosing Logo Colors That Work for Web and Print

If you’re a designer who works in the digital space, you know how to use logos on the screen. But how do you specify a logo color for print when it only exists in RGB?

With a little bit of upfront work, you can completely bypass this problem.

For instance, the way you perceive color is dependent on how and where you’re looking at it. If you’re outside, is it a sunny day or is it overcast? If you’re inside, are you under fluorescent lights or color-correct lighting? Are you viewing color on a calibrated monitor or your five-year-old Macbook? There are so many variants.

Remember high school biology and chemistry classes? We learned about “controls,” and how to use a control to measure deviation. Um, that, and other random, nonsensical things that I quickly forgot (sorry Mr. Frost)!

BRIDGING THE GAP

In the world of graphic design, we have a fantastic control. It’s called the Pantone Color Bridge. It is aptly named Bridge because it bridges the gap between digital colors to printing inks.

Let’s get a closer look at the Bridge.Pantone232

The left swatch is printed in a spot Pantone ink, PMS 232 C. These spot colors used to be called PMS colors, although Pantone doesn’t call it that anymore. The ‘C’ in the name means that this color resides in the Coated fan deck. The left swatch also indicates the RGB and HTML hexadecimal formulas for that color.

On the right is the CMYK equivalent for the spot color on the left. In this case, the swatch is printed with 3% Cyan, 60% Magenta 0% Yellow and 0% Black. The ‘CP’ in the name means that this is a Color Process specification.

Note that the swatch on the right is lighter and less saturated than the swatch on the left. This is as close as these two colors can get. Ever.

If you design a logo that uses the RGB formula above, and you have a print job that needs to match, you now know:

1. The Pantone number to specify or the CMYK equivalent to use in your file (good!)

2. This is as close as it is going to get (bad!)

This next example shows two colors that are nearly identical.PantoneRhod

Again, the left swatch is a single ink, Rhodamine Red, and the right swatch is it’s CMYK equivalent. WOW. It’s hard to tell them apart, right?

If you specify Rhodamine Red in the Bridge you now know that it can be replicated closer to a CMYK equivalent. BINGO.

The Pantone Color Bridge set is not inexpensive, but it will save you loads of heartache and money in the end.

Here’s a little bit of background on why we need a tool like the Pantone Color Bridge.

When you look at a color, it is being interpreted by the source.

Outside in a garden, you see a pink rose. The color of that rose is going to be affected by the sunlight.

  • Is it bright or overcast?
  • Are you wearing sunglasses?
  • Do you have a degree of color blindness? (probably not if you are a graphic designer!)

When you look at color on a monitor, is it calibrated? Is it new or old?

And when looking at a printed sample, what is the lighting, the type of color — spot or CMYK, is the paper coated or uncoated?

COLOR GAMUT

All of these examples describe gamut. Color gamut is the range of color that can be created by a device. This diagram shows the gamut of color perceived or reproducible by different color systems or “devices.”

gamut-diagramrgb

gamut-diagramprint

The outer edge is the visible gamut that our eyes can perceive. The left diagram shows the gamuts of various RGB profiles (because you are viewing this on a monitor, you are not “really” seeing the true visible spectrum, which is why there are a zillion greens in nature). And isn’t it crazy that there are multiple RGB gamuts? The diagram on the right contains Pantone, CMYK, Hexachrome and SWOP CMYK gamuts.

gamut-diagramrgbtoprint

If you are designing a logo for a website, in the RGB space area (the triangle at left, outside the inner CMYK area and you want it to match when printed, you are going to stress out. As you can see, in the lower diagram, the grayed out area is showing everything within the Adobe RGB gamut that is impossible to create with CMYK inks. Nearly the full orange wedge is outside the CMYK gamut. The Pantone bridge illustrates this for the Pantone universe.

Study this color model and you’ll see the areas to avoid. If you stick to the CMYK circle you will be able to match colors across CMYK, Pantone, and RGB. This may seem very limiting, but the truth is that in the CMYK circle, there are MILLIONS of colors. Also, don’t forget that rarely monitors are not calibrated, so reducing your RGB color space to a narrower CMYK reproducible space may increase your RGB consistency as well.

Before Pantone developed this product it was a real b*tch to try to match identity, and we had to keep logo colors in a really narrow spectrum. Now with the Pantone Color Bridge, we have millions of colors to work with!

Confused about digital printing?

For a limited time to can get the actual decision tree in my book, for free! The ultimate tool for figuring out if a project can be digitally printed or if it needs to go on press. PLUS you'll get a heads up when the Kickstarter campaign launches.

We respect your privacy.

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