The Resolution Issue
High resolution printed images are recognized by fine lines, sharp details, clean edges, subtle variations in tone, and no noticeable color stepping or dithering of edges. Resolution is measured in dots per inch (dpi) also referred to as pixels. For best quality, ProGraphics requests images have a resolution of 300 dpi. In other words, a printed 1 x 1 inch square image needs to have a resolution of 300 x 300 pixels. If you want to print an image big enough to cover an 8.5 x 11 inch letter-size page with bleed, the resolution should be at least 2,625 x 3,375 pixels.
In comparison, the resolution of most images meant to be viewed on a computer screen or monitor is typically only 72 dpi. (Even though screen resolutions have increased in the last 30 years, most Web designers continue to use this standard, because images look OK, and it keeps the file size small.) So, a 72 dpi 3 x 5 inch image which was pulled off the Internet will have a resolution of only 216 x 360 pixels. After converting to 300 dpi as required for printing, that image will be a mere .75 x 1.25 inches. By the way, don't be tempted to open up a low resolution image in a photo editing program such as Adobe Photoshop and add resolution by resampling. This will only add to the file size, not the quality.
Occasionally, it is necessary to scan an original document consisting of type or handwriting, such as a signature or a letter of authenticity. In order to keep the type sharp-edged and readable, it should be scanned as black and white bitmap line art, 1200-2400 dpi (minimum 600 dpi).
It is important to understand the difference between raster- and vector-based design elements. Raster-based design elements, also referred to as bitmapped or pixelized images, are graphics made of hundreds or thousands of individually colored dots or pixels. All digital photographs are raster images, whether they have been snapped with a digital camera or a smart phone, or they are traditional photos which have been scanned onto a disc or a computer. Also artwork which has been scanned, touched up or created in a photo editing program such as Adobe Photoshop are raster-based. Pixel images should be converted to CMYK color mode and may be saved as JPG, composite EPS, or TIFF files. They should be 300 dpi resolution at 100% scale, or close to the size and scale you want them to be printed. Use a camera with at least 5 megapixels. Also use the higher resolution/less images setting of a digital camera for best quality.
Vector graphics are graphic files made of mathematically defined points, lines and shapes resulting in scalable smooth-edged images, no matter how big or how small you make them. Vector graphics are great for logos or other images where type is an integral element. Vector graphics are created in a drawing program, such as Adobe Illustrator and they should be saved as EPS, AI or PDF files. A word of caution when specifying line widths; a hairline rule will often print acceptably on a laser printer but may be so fine that it is barely visible when output at high resolution on the printing plate.
Fonts are essentially vector-based images. They can be scaled up or down just by changing the point size, and remain smooth edged and readable at nearly any size. Generally, ProGraphics recommends you DO NOT set type in a raster-based program such as Photoshop, because it will have soft fuzzy edges. Even at 300dpi, rasterized type is not as precise and clear as vector based type. An exception is scanned, super high-resolution (1200dpi) bitmapped type if you are not able to, or permitted to reset the type.
Most preflight headaches arise from missing fonts. To avoid potential problems we recommend that you supply all the fonts you use to create your document when submitting files for printing. Also include fonts that were used to create placed vector files, such as the font for the company logo you created in Adobe Illustrator last year and placed into your new design yesterday. You can avoid font issues by using the "create outlines" feature in Adobe Illustrator or InDesign, but then you lose text editing capability, so make sure to always save a version before fonts are outlined.
Each typeface typically has two sets of files, printer fonts and screen fonts. We need both sets to process a file. We do not recommend applying text attributes from within a page layout program. If you need to use a bold, italic and regular typeface, choose a font family that includes these different fonts. Windows/PC fonts are generally not cross platform compatible, so if it is necessary to change platforms on a document we need to know the exact description information of the fonts being used.
NEVER rely on your monitor to choose a color. Color varies from monitor to monitor and it WILL look different when printed. Instead, we recommend you choose colors by using a Pantone Process Color swatch book which has spot colors printed side-by-side with comparable 4-color process screen mixes. Use the screen mix percentages specified in the swatch book and you will have an accurate idea of how your colors will print. Click here for a description of spot versus 4-color printing processes.
All four-color process images placed in your design should be CMYK, not RGB.You may design with spot colors even if your design is being printing as 4-color process. If your job is being printed as 4-color process, ProGraphics will use a Raster Image Process (RIP) which converts spot colors to CMYK. Be aware some spot colors are out of gamut and cannot be reproduced with the 4-color process. Also, different applications and different RIPs may be programmed to use different percentages of CMYK to simulate spot colors.
It is recommended that fine lines and type be printed in one color, typically black. If you convert an RGB file to a CMYK file, make sure that type which is intended to be printed as black is black only. If you want small or fine line type to print in a color, we recommend printing it as a spot color, rather than a CMYK screen mix, to avoid any registration issues.
If you are designing a piece with a solid black background, add undercolor in order to avoid specks and to create the illusion of a flawless, uniform, dense black. A combination of 60 percent cyan, 40 magenta, 30 yellow and 100 black works great for a rich black.
Spot Colors, UV Coating and Spot UV
If you are printing in spot colors, or a combination of both 4-color process and spot color(s), ProGraphics will use a different RIP to output a separate printing plate for each spot color and process color. In this case, your files will have to be very specific about which color(s) will be printed as spot. Choose your spot color using a PMS swatch book and specify the spot color(s) in your swatches palette. Clearly indicate elements intended to be printed as spot color(s) on a proof. All other non-spot, 4-color elements must be CMYK color mode.
UV coating is a transparent coating which protects your printing from sun fading and scratches. It can be glossy or matte.You can have it applied overall or create contrast and texture by applying it only in designated places, referred to as Spot UV. ProGraphics will apply Overall UV as a finishing process as instructed. Overall UV does not need to be added into your design file, but Spot UV does.
Since UV coating is transparent, you need to indicate where you want the Spot UV to print. Here's how... Create a new swatch, make it 100% Magenta, specify it as a spot color in your swatches palette, name it "SPOT UV" and assign it to the shapes wherever you want spot UV to print. You can also make spot UV shapes in inDesign, Photoshop or Illustrator using the same color designation, "SPOT UV". Spot UV is either 100% or nothing. Don't apply a percentage of spot UV less than 100%. We recommend you put all the spot UV shapes on a separate layer in your document. Select all your spot UV shapes and make sure the Window>Output>Attributes are set to OVERPRINT.
To check your colors, open "Separations Preview" in InDesign, "Overprint Preview" in Adobe Illustrator, or "Output Preview" in Adobe Acrobat. With the preview turned on, Spot UV will appear transparent and you should be able to see the image underneath. Run your cursor over the graphics to see the percentages of each color in each graphic element. If you are printing a SPOT UV or a DIELINE, uncheck them to turn them off and confirm they are NOT knocking out the color underneath. Also check to make sure black type and thin black lines, particularly in technical drawings, are printing as black only.
If you need packaging for a product, it is best to give us the product and our package designer/CAD operator will create a die that cuts, folds, glues and fits your product perfectly. ProGraphics will convert the dieline and supply it to you as an Adobe Illustrator file, built to the exact size of the dieline plus .125 inch bleed, for the placement of your graphics. If you supply your own dieline, it will need to be converted into a DXF file so that it can be made into a die.
The dieline must be specified as a spot color named "DIELINE", and set to overprint, so it does not knock out the colors underneath. You may place your artwork on a separate layer(s) in the Adobe Illustrator file or you may build an InDesign document the exact size of the dieline, plus .125 inch bleed, and place your graphics in InDesign. Do not put printing on the glue flaps. Glue works better on unprinted paper.
Trapping is affected by many factors and is therefore a task better left to us here at ProGraphics. To avoid a potential problem, try not to let two gradients or vignettes of contrasting colors butt up next to each other without a keyline or space between them. If your vector graphics need specific trapping, it should be done in a vector drawing program, such as Adobe Illustrator.
Make sure all elements (photos and graphics) that run off the edge of the page have at least 1/8 inch bleed beyond the final trim size of the document. Some jobs may need even more bleed, depending upon the steps involved to produce the final product, such as litho labels which are laminated to corrugated board and then diecut. Use your judgement, more bleed won't hurt.