June 1, 2000
Let's get into the printing process. I know, you're saying, "YUCK, YUCK". Well if you're going to be successful as a designer you'll have to know how to set up a file for outsourced printing. Of course you may be taking the other trail to purely designing for the world wide web. But there is that occasional request from someone who just loves your stuff, and they just have to have you do some designing for them. Great! But guess what, you'll have to know this printing stuff or you'll be left in the dust eating bugs. Or just become a 3D designer instead and ignore everyone because you're just too good for "that stuff".
Well, let's set it up quick and dirty. Here's the process in a nutshell:
Step 1. Choose your printer.
Step 2. Choose File Page Setup.
Step 3. Adjust the halftone screens, if needed.
Step 4. Adjust the transfer function again, if needed.
Step 5. Choose File>Print.
Wasn't that easy? Well that's the end of the lesson. Just joking son.
Here's an important note from your announcer: Never take a shortcut when setting up a file for printing.
Step 1 - If you're using a PC, select Start>Settings>Printer. To access the printers, right-click and choose a default printer. If you want to add printers, click Add Printer. You'll be asked to supply either your Windows disk or the manufacturer's printer disk if adding a printer. This is a good way to add printers that you'll be preparing a file for to be sent out.
Step 2 - Standard Options: Now you need to setup a page by accessing File>Page Setup. (The Page Setup dialog box will vary according to the printer you have selected. In this case, I'll be using my own printer for demonstration purposes which is an Epson Stylus Color 800.) Here are the four common options you'll always see with every printer: paper size, source (Windows only), orientation, and reduce and enlarge (Mac only). If I select on the Properties button, it will take me to a dialogue box specifically made for the Epson Stylus Color 800. In this box I can specify print quality, black & white or color printing, and tell it what kind of paper I'll be using.
Special Printing Options: At the bottom of the Page Setup dialogue box you'll encounter a special setup area especially for Photoshop. Here are what the buttons are for - Screens: access a dialogue box for size, angle, and shape of printed halftone cells. Transfer: redistribution of shades in the printed image. Background: this button is designed specifically for slides printed from a film recorder and you can choose a color to by using the Color Picker to surround the printed image. Border: print a border around the selected image (also specifically aimed at slides printed from a film recorder). Bleed: if outputting to an image setter, this selection allows you to print in the non-printable area of the page. (An image setter prints on huge rolls of paper or film which allows you to print outside the standard page dimensions. To specify a bleed width, click on the Bleed button and enter the coordinates. (24 points is a good number.)
In continuation of Special Printing Options, all the buttons excluding Negative, Emulsion Down, and Interpolation, append labels and printers marks to the printed version of the image . Here are what the boxes are for:
Caption: This is used to print a caption below the image and prints in Helvetica 9-point, and really it just helps you to remember what you were doing with this image when all your brain cells have popped opened and fell on the floor, or when Agnes gets a hold of the image and wants to know what you were up to till 9:00 at night. Just tell her you were trying to rescue any brain cells you could that the janitor hadn't got to yet.
Calibration Bars: No, it's not a new energy food. It's a 10-step grayscale gradation which starts at 10% black and ends at 100% black. What it does is guarantee that all shades are absolute. If not, you'll be disbarred from ever using Photoshop again. Seriously, you'll discover that your output device is out of whack and needs to be calibrated. When printing color separations, the Calibration Bars tells Photoshop to print a gradient tint bar and a progressive color bar, a necessary attribute for professional printers.
Registration Marks: Something you get after taking your car in to be smogged. What this does is print 8 crosshairs and two star targets near the four corners of the image. When printing color separations you MUST have these. They are the means for ensuring exact registration of cyan, magenta, yellow, and black printing plates. If you are printing a composite image, you will not need this.
Corner Crop Marks: This will print 8 hairline crop marks to indicate where to cut the image for traditional paste-up work.
Center Crop Marks: Prints 4 pairs of hairlines forming a cross which mark the center of the image. Two are located above the image and two on the sides.
Labels: Prints the name of the image and color channel in 9-point Helvetica. This is helpful when printing large quantities as it helps matching up printouts with documents on disk.
Negative: This prints blacks as whites and whites as black. The in-between colors switch accordingly. This is used by printers to print composites and color separations to film negatives.
Emulsion Down: This is the side of the film which the image is printed. If this is unchecked, the film will print from an image setter emulsion side up. If it is checked, Photoshop flips the image so the emulsion side is down. This is useful when you print film from an image setter. It should be set to the preferences of the commercial printer.
Interpolation: This feature deals with PostScript Level 2 or later printers, it instructs Photoshop to antialias the printed appearance of a low-resolution image. The output device then resamples it up to 200% and reduces the image to it's original size using bicubic interpolation which creates a less-pixelated image.
Step 3 - What is changing the halftone screen? Here is a brief explanation how printing works: Suppose your image has purple in it and your commercial printer needs to lighten the purple. Should he a) find a lighter purple ink to use, b) water down the purple that he already has, or c) accomplish the task using halftoning? Halftoning is a process of organizing printer pixels into spots of halftone cells. Depending on how close the colored pixels are on a white background determines how light or how dark a color appears. These cells are so tiny that the human eye on first glance cannot delineate between the color and background. If you looked very closely or used a magnifying glass you would see what I mean. Large cells appear to be dark shades while small cells appear to be lighter shades. The cell size is measured in pixels and the maximum size is a function of the number of cells in an inch called screen frequency. Here is a mathematical equation which signifies how this works: if your printer defaults to 60 halftone cells per linear inch and the printer's resolution is 300 ppi, then each halftone cell must measure 5 pixels wide or (5 pixels tall (300(60=5) for a total of 25 per cell (5 squared). Now if you turn off all pixels in a cell, it appears white while if you have them turned on, you'll get solid ink. Depending on the number of pixels you have on determines what shades you'll get. You can turn 0-25 pixels on and the printer will create up to 26 shades. You can change angle, size, and shape of individual halftone cells. Open Screens in the Page Setup dialogue box.
Ok. You're asking what all this stuff means on the Halftone Screen dialogue box. Well let me tell you:
-Use Printer's Default Screens - check this box if you want to accept the default size and shape settings built into your printer's ROM. When this is checked, all other options are dimmed.
-Ink - this allows you to specify an ink that needs adjusting if your image is in color. If the image is grayscale, you'll not get this pop-up menu.
-Frequency - this option allows you to change the number of halftone cells that print per linear inch (lpi). Higher screen frequencies results in a professional-looking piece. On raising the frequency value, you'll find the output device will decrease the number shades due to the shrinking of each halftone cells. Here's the formula: Number of shades = ((printer resolution divided by frequency) squared) +1.
-Angle - on entering a new value in the Angle option box, you can change the angle of the halftone cell and how it prints. If you'll be printing color composites to an ink-jet printer, thermal-wax printer, and when printing color composite separations, Photoshop calculates the best Frequency and Angle values for you. You should not mess with this option for these selections unless you are an expert. On the other hand, if you dealing grayscale images, you can mess with it all you want.
-Shape - the default halftone cells shape for PostScript printers is usually round but there are 6 varieties to choose from. If you're familiar with writing PostScript code, you can select Custom and write your own code for shapes.
-Use Accurate Screens - if you're using a PostScript Level 2 printer or later, select this option.
-Use Same Shape for All Inks - this option allows you to select for the halftone cells the same size, angle, and shape for all inks.
-Auto - this feature opens up the Auto Screens dialogue box where automation of the halftone editing process occurs. In this box you would enter the resolution of your output, and screen frequency. Once you have completed that step and pressed enter, Photoshop will calculate the best screen frequencies for all inks. Use this feature when printing full-color images because Photoshop takes command of the situation and negates human error.
- Load/Save - load and save settings to disk for future use.
Here's an interesting item you should keep in your memory banks: hold down the Alt key and click on the Save button; the Save button changes to read >-Default. To restore the original settings, press Alt and click the Load button (<-Default).
To transfer these settings to another program such as QuarkXpress, save the image as an EPS file, and check to make sure Include Halftone Screen is checked in the EPS Format dialogue box. Make sure that these settings are compatible with the intended output device. The types of errors you can encounter is specifying 60 lpi to a 3,600-dpi image setter. Call your service bureau or printer before saving the image. If you don't check first, you will be charged a large sum of money for this error.
Step 4 - Let's specify a transfer function! Are we having fun yet and what is a transfer function? A transfer function gives you the opportunity to change the way on-screen brightness values map (transfer) to printed shades. If you know your printer prints overly dark or overly light, you can compensate that fact by entering numerical values or percentages in the Transfer Functions dialogue box that will fix those irregularities. It's a matter of getting to know your printer. Below are the options in the dialogue box and their meanings:
-Transfer Graph - this is where you map the screen brightness to the printed equivalent. How do I read the graph? The horizontal axis is the screen brightness values; the vertical axis is the printed shades. The curve shows the relationship between on screen and printed colors. The lower left of the graph is the brightness or white area while the upper right of the graph is the darkness value. As with the Curves graph, you can click inside this graph and add points and adjust.
-Percentage option boxes - these boxes are so named for the on screen brightness values and any changes in these boxes will be reflected on the graph.
-Override Printer's Default Functions - if you have trouble making your settings take effect, click on this function to apply the transfer function.
-Load/Save - this is standard settings for saving and retrieving previous transfer function setups that you saved. Click on Alt+click to retrieve and save settings.
-Ink Controls -this is used for printing full-color images. When selected, five options appear. These options give you the opportunity to apply different transfer functions to different inks. If want to apply a different function to each ink, click off the All Same button.
Step 5 - Here's where we select the File>Print option to print the pages. Let's look at the options in this dialogue box:
-Copies - easy enough to understand.
-Print Range - you can print from 1 to 999 copies from here. But more importantly you can select an area of the image with the marquee tool and tell it to print just that area.
-Print to File - (PostScript printing) save a PostScript-language to disk. Deselect to print to your printer. The only reason to use this feature is to capture printer's marks.
-Space - this feature deals with color space. Version 5 or later lets you convert to any color space for Photoshop, Apple's ColorSync, or Kodak's ICC CMS. You need to choose the correct profile for your printer. If you are unable to locate it, use RGB Color space (located in File>Color Settings>RGB Setup). Or choose CMYK Color which will output the image as if you had converted to CMYK. For best printing results, I suggest printing via RGB.
-Encoding - this is used if your network does not support binary encoding or attached through the local parallel printer port, instead of the network, choose ASCII for transporting PostScript data in text format.
-Setup (Windows only) - Page Setup dialogue box.
Once you have run through these options, press Enter and your printer will begin printing.
And that is the first printing lesson entitled Printing 101 - Printing a Composite Image. In my next lesson I'll show you how to create color separations. You're thrilled, I can tell!
Copyright 2000, Jacquelin Vanderwood, All Rights Reserved