I am happy to announce the All New SimRip. Check out the video.
SimRip is all new and improved. Convert any multi-channel or CMYK document to high resolution printable halftones within Adobe Photoshop®. The code has been streamlined for faster processing. SimRip now works from any open or closed document. Enter angle and dot size settings in a single dialog for all channels. Output resolution and transfer function too.
(Update: this is the previous version of SimRip. Please see the new version above.)
In this video I start with a ready to print color separation. You can see the channels in the top left. First, I close the separation I am about to rip, and load the SimRip script from the Scripts menu. I am presented with an options window, and choose the options I prefer. Next, I am prompted for the document to rip, and select it in the Open window. The script makes a copy of the file and processes the channels.
(Edit: this post discusses the previous versions of YRGBK.)
The first steps to making a printable color set from the YRGBK color set are to set the black point of each color channel, then adjust for dot gain. In the first, we are making sure that the darkest pixels representing each color are printing at 100%. The second step is to adjust for gain in the printing process.
The concepts apply to custom color separation in general, regardless of how the colors are generated. The YRGBK script merely provides a pretty good head start.
Black point, Dynamic Range, and Ink Coverage By setting the darkest value to 100%, we increase the total printable range of each color channel. In addition to increasing the range of values we can represent, setting the black points also ensures good ink coverage in colorful areas of an image. This in turn reduces the amount of pressure needed to get a good print through a screen, improving both detail and dynamic range on press.
To set the Black point, select a spot color channel • From the menu choose: Image/Adjustments/Levels • Move the Black slider to the first set of pixels in the histogram
Dot Gain With the Black point set, the next step is to adjust for dot gain in the color channel. By applying a curve to reduce the density in the mid range, we can compensate for the gain that occurs on press. A standard adjustment is generally required, although making a custom adjustment for the particular image is best. (Before making a dot gain adjustment, be sure to set the spot color setting, in the color settings menu, to the correct dot gain for your print setup. This setting modifies the spot color channel preview when more then one color channel is visible.)
To adjust for dot gain: • Select a spot color channel • Open Curves from the menu: Image/Adjustment/Curves • Click on the center (50%) of the diagonal line and move it down to the 30% range. • This adjustment can be customized to suit the image, spot color, and black point setting.
Setting a custom color Increasing the value of a channel increases the amount of color printed. The color of a spot color channel should also be considered when setting the pixel density. Using a less saturated, printable ink color compensates for an increase in color density.
• The Use ink colors option in the YRGBK script sets the color channels to printable ink colors.
I will get back to talking about painting soon, but first I am going to take a detour through the world of pre-press. Eventually I will tie the two together as I continue to describe my workflow. I have been super busy with several projects, and am looking forward to sharing.
About Actions Actions are flexible in their simplicity and ease of use. The downside is that an action is a very linear process, as they only operate through the recorded steps in Photoshop.
To create an Action, open the actions window from the Windows menu. Along the bottom of the Actions window you can see the usual icons for creating a new item and an item folder. Additionally there are icons for recording, starting and stopping an action. By clicking the New Action icon, (looks like the new layer icon) and clicking record (the round icon) Photoshop will start recording the steps made. Clicking the Square icon will stop the recording, while clicking the play Icon will replay the sequence.
Actions are very handy if you have a lot of images to process in the same fashion, or if you have a complex process that is used often. I will also use actions as a rapid test bed to develop concepts and theories for my prepress work. I can also store ideas about processes I dream up. If you use Photoshop to get work done take a look at Actions. They are simple and fun, and quite powerful. Actions can be saved as action sets, or exported as Droplets. A droplet is a mini app that contains the actions and supports drag and drop for image files.
Using an existing script file in your workflow can be a major time saver. Photoshop comes with several useful scripts already installed.
To everyone who has provided feedback, comments and encouragement on the new scripts I want to say THANK YOU! You are making it happen! New tutorials are on their way.
The YRGBK droplet is a color separation script for Adobe Photoshop which generates a set of printable, complimentary colors from an RGB document. I use this script to begin the separation process. Get it here.
Base color generator A finished image can be processed through the YRGBK script to create a set of standard colors for color separation work. The resulting channels can be used to build a simulated process color separation, or used as a base for spot color separation. By starting with a base set of standard colors, I can be sure all the color data is included in the separation. Depending on the image, some color channels will contain little or no pixels and can be discarded, while additional spot color channels can be added to customize a color separation.
A standardized approach The YRGBK script provides a standardized approach to generating simulated process and spot color channels. The colors are pulled directly from the hue values in the Lab mode. The concept is simple and is based on the separation of color into Hue, Saturation and Value.
The Value in an image is handled by the L channel in the Lab mode, which is converted into printable Black and Gray channels. The remaining color channels are broken into 7 separate Hues; Yellow, Red, Green, and Blue, plus Cyan, Magenta and Purple. The Saturation is determined by the density of each channel.
This color wheel shows how the base colors and the Luminosity can be combined to make a 3 dimensional color sphere. Any color within this sphere can be represented with the combined channels.
Color Separations for Screen Printing