Why saving textures and line-art as 1200ppi Bitmap Tiff files is a good habit for just about everyone.
We're often asked why we supply textures in many of our texture packs as 1200ppi Bitmap Tiff files. To many users, a 1200ppi file seems like overkill but fear not, there is rhyme to our reason and reason to our rhyme.
Whether you're a texture savvy designer or an illustrator aiming for a screenprinted aesthetic, it's all about quality, usability and being press-ready at a moments notice.
Reason 1: High Quality, Low File Size.
Bitmap Tiff files contain only a single 1 Bit black channel with pixels that are either black or white with none of the shades of grey contained in a regular grayscale image.
To demonstrate, I've combined some line art, grit textures and halftones to into two different formats to compare below.
At screen resolution they look fairly similar but when we zoom in 300% you can see our 1200ppi Bitmap Tiff remains ultra crisp and retains all the fine distressed details of our line-art and textures whilst there is visible pixelation and shades of grey on the Grayscale image.
You'll also notice that the file-size of the Bitmap Tiff is quite small relative to its very high resolution. Even though it is 400% higher in resolution than it's grayscale buddy, the file size is only 30% higher. That's pretty good bang for buck considering the increase in quality.
Reason 2. Usability.
When we place a 1200dpi Bitmap Tiff into Adobe Illustrator or InDesign, the app recognises only the 1 Bit black channel and not the flattened white background meaning we can use the image transparently and change it's colour as we would any vector object or shape.
Grayscale images on the other hand, can only have color applied to them if flattened but once flattened cannot be used transparently. ¯\_(ツ)_/¯
Let's compare what happens when we place both files into illustrator and apply color.
Notice how Illustrator recognises only the black channel of the Bitmap Tiff whilst the Grayscale image renders as a flattened file.
Taking advantage of this technique I can now quickly duplicate my illustration, drop in some additional Bitmap Tiff texture files from my texture stash and draw-in vector shapes with the pen tool much faster than if I was messing around in Photoshop with my canvas resolution set in stone.
QUICK AND DIRTY!
With all this in mind, I personally prefer to prep and process my textures, distressed line art and graphic assets in Photoshop first before laying them out in Illustrator where I can experiment with compostion, add type and play with colour with much more flexibility.
The advantage of this process is that I can work with a level of texture and detail that is impossible to achieve in Illustrator alone without the clunkyness of trying to create page layouts in an app designed primarily for image processing and having fun with family portraits.
- When using Illustrator and InDesign, Bitmap Tiffs place far less strain on your computers graphics card and memory than vector textures which can grind your machine to a halt if they contain too much detail.
- If you use Illustrator's Live Trace function to trace scanned graphics and line-art you'll acheive much better results when vectorizing a 1200ppi bitmap Tiff than a 300ppi greyscale image.
Reason 3. PRE-PRESS AND PRINT QUALITY
The irony of discussing press quality as it relates to distressed, textured and otherwise intentionally fucked-up artwork is definitely not lost on me, but understanding some of the print-production principles behind the use of Bitmap Tiffs is definitely worth the time.
Ever wonder why when you save a Press Quality PDF from Illustrator or InDesign the default setting for Monochrome Bitmap images is 1200ppi whilst Colour and Grayscale Images are only 300?
This is essentially because Adobe assumes you know the difference and that if your file contains Bitmap Tiff images you want them to be treated in a similar way to vector art, with no shades of grey or line screen applied.
When we send a file containing a Bitmap Tiff image to print the app and your print suppliers RIP automatically recognises the image as line-art and 1200ppi is considered the minimum resolution required to print detailed line-art on a modern digital to plate (DTP) press or high quality silkscreen mesh (even if your artwork is textured and distressed).
There are of course legitimate reasons you might prefer to print lower resolution grayscale or CMYK files (when reproducing delicate pencil illustrations or images containing subtle textures for example) but as a rule, if you want your line-art and textures to appear super crisp in print, save them as 1200ppi Bitmap TIffs.
To illustrate, let's take a look at what happens if we print both file formats on a standard laser copier.
Notice how the 1200ppi Bitmap Tiff is printed ultra-crisp whilst the printer interprets the 300ppi Grayscale image's shades of gray as a line-screen or halftone?
This is really important when supplying separations for screenprinting if you want to retain the crisp edges of your artwork and avoid unexpected halftones appearing in your line-art.
For best results when the stakes are high be sure to talk to your printer about their particular pre-press specifications.
To save your own textures and line-art as a 1200ppi Bitmap first ensure your image is in Grayscale mode then resize your image to 1200ppi with the Resample checkbox checked.
Then go to Image Mode > Bitmap > 50% threshold.
Finally, don't forget to save your file as a .tif File > Save As > Tiff.
To avoid obvious pixelation, be sure to enlarge your image to 1200ppi before converting to Bitmap. If Bitmap mode is greyed out it's because your image must already be in Grayscale mode before converting to Bitmap.
Now you have yourself a press-quality texture or graphic file ready for use in Illustrator or InDesign.
Posted by Andrew Fairclough.