Chapter 4 starts off explaining about some of the first cameras, scanners and other photographic resources. They were huge, very slow, and took a highly skilled graphics arts professional to work them. As time has gone on, technology has improved and images have been moved from film to digital pixels. Pixels are the smallest unit of information in a digitized image. Pixels are little square boxes that altogether make up an image. Now that we have digital cameras, we can upload our photographs straight onto our computers. Most cameras today save their images as JPEG's which is a compressed format to make file size smaller. However, professional cameras can save can save their photos in a RAW file format which is an uncompressed format. This means that you can change or manipulate the photo without losing information. However, since it is uncompressed it is a huge file size it takes up a lot of memory. In the end you have to convert it to a different format to get it produced.
Resolution of an image is a different matter. Mostly, it is measure in pixels per inch(ppi). For web the standard is 72 ppi at final size. When we had smaller hard drives there was a debate at what resolution to print images at. However, since we are now advanced and have huge hard drives the standard for printing images is 300 ppi. Bitmap images are often called "line art images". they contain only black and white pixels. Mostly bitmaps are very high resolution with small file sizes that provide very clean images.
The chapter then goes into the downfall of scaling your image up or down. Also with making corrections or changing an image. They say it is a lot of work to fix and a lot of stress to get it to look right so try not to do it. Cropping images should be done when actually putting the photo in your layout. Another idea is to save the crop as another image. Rotating images can be tricky but to keep the image in the best possible detail use 90 degree increments. If you do rotate or change you image expect some lost details.
The last two big things they talk about is appropriate and inappropriate image formats for print. first it goes through the appropriate formats. The most commonly supported image file format is TIFF(tagged image file format). It is accepted by most applications that accept images.Photoshop EPS(encapsulated PostScript) is a flexible file format but has a big file size. TIFF and EPS have been the two most used formats. Then we have Photoshop Native (PSD) document. It's use has been mostly used for images in Photoshop and since old habits die hard they still flatten PSD's and use TIFFS and EPS. Next is a Photoshop PDF(portable document format). The pixels are put in a PDF wrapper that can contain vector and type elements without converting the vector parts to pixels. It also talks about RGB versus CMYK in this section. It tells us that scanners and digital cameras see in RGB but no one used RGB for print anymore. Therefore they tell us to make sure to convert files to CMYK before you print or you will be frowned upon. Then it goes into inappropriate image formats for print. It goes through four different formats. The first is Portable Network Graphics(PNG). These are images that are intended for web and onscreen use because it has no support for CMYK color space. The second one is BMP(abbreviation for bitmap). It also does not support CMYK even though it has color depths up to 32 bits(millions of color). It is also unsuitable for print. The third is Graphics Interchange Format(GIF). GIF is good only for web but not for print. The last one is JPEG(Joint Photographic Experts Groups). It has a small file because it has a lossy compression. That means that is discards information in your image to make the file size smaller. JPEG's are not altogether bad but you are better off saving it as something else and not using it to print.
Chapter five is all bout Vector Graphics. Vector graphics are pixel free and are not subjected to the scaling restriction that rasters are. There are different vector file formats and its good to know which ones are good for print. Encapsulated PostScript(EPS) is the most common file format for vector artwork. It is a contain for PostScript information that makes other applications understand it. While you can place EPS files into a wide range of applications it has to be in the originating application to do any editing. EPS files can be placed but they cannot be opened in other applications, you have to open and edit it in its originating application. Most often time you don't have to use EPS files now because you can use the native file format for that app. And if you are not placing artwork into another file but saving it as finished artwork the best way is to save is as a PDF to protect it from unwanted editing. Then there are vector formats that are not appropriate for print. Such as Microsoft Windows Metafile Format(WMF), Enhanced Metafile Format(EMF) and Raster Formats. WMF's and EMF's are intended for applications such as Microsoft Word and Power Point and do not support CMYK; therefore unappropriated for print production. You can export rasters into TIFF, JPEG, PNG and BMP but if you don't need to raster you vector artwork then export it and keep your native file format.
It also talks about how to handle text in your vector artwork. The most common methods are embedding and outlining. Embedding fonts means that you can embed a font into an EPS or AI file for placement in another application. It will be available for display and printing but not editing. Outlining text is simply creating outlines around text so you don't have to worry about embedding fonts. You might lose detail in you font but you don't have the risk of losing them.
To incorporate images into vector files you can either link the images or embed them. Most people prefer linking images; however you can embed images in your drawing when creating EPS or AI, to make sure that your files won't get lost. Embedding does add size to your file. But what if you want to edit the image and its not your artwork? Simply copy to the clipboard, open Photoshop and edit it in Photoshop.
You can avoid unnecessary complexity by simplifying your paths. Create more with less. Using less points makes it look smoother and easier to print. To make life eve easier use the programs for what they are intended for. Use Illustrator for artwork and InDesign for Page Layout.
Sources: All content came from our textbook :Print Production by Claudia McCue.
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