Research information to develop the content for my Issuu publication and design outcome for the 'What is design for print?' guide book. This particular section of research features print marks, crop marks, and registration- all useful tools for ensuring high-quality printed outcomes. Development and content of this research can be found on my Design Practice blog in the forthcoming days and weeks.
DEFINITION OF CROP MARKS//REGISTRATION//REGISTRATION BLACK
Crop mark may refer to
- in printing, marks placed at the corners of a form to indicate where the page is to be trimmed
- (Registration mark) In color printing, registration is the method of correlating overlapping colors on one single image. There are many different styles and types of registration, many of which employ the alignment of specific marks.
- (registration mark) A mark added to a document for color printing to aid the commercial printer in lining up copies of the same page.
It is therefore not correct to simply define registration color as 100% of C,M,Y,K, since it will rather be 100% of whichever colors are used in reproduction.
It is a special purpose color, and as such is not generally used to print black text or grayscale graphics.
Instead, registration black is used for printing crop marks, or "registration marks". When proofs for each color are generated on separate pieces of film, use of registration black makes crop marks visible on all channels, providing a useful reference for alignment. A thin line printed in registration black can also be used to check whether the printing plates are lined up.
PostScriptThe PostScript printer description languages supports registration black, starting with PostScript language level 2. This is done by referring to a spot color with the special name All. This never generates a spot plate. Instead it marks all of the plates that are there. The All color space can be used with a tint value between 0.0 (no mark) to 1.0 (full intensity). Generally, only 1.0 would be used.
The name "All" might not be used in the user interface of a design program, especially outside English language speaking areas. However, the spot color must have the exact name "All". As a side effect, it is impossible in PostScript to create a normal spot plate with this name.
Printing registrationIn color printing, registration is the method of correlating overlapping colors on one single image. There are many different styles and types of registration, many of which employ the alignment of specific marks.
PurposeWhen printing an image that has more than one color, depending on the method of printing, it is necessary to print the image one separate time for each separate color. Each one is called a "color run," and they can be pulled from the same surface, inked differently, or from a completely different surface. So that the final image is consistent, and so each of the colors lines up correctly, a system of registration is necessary. Different printing devices have different methods of creating separate color runs.
Types of (stone) lithography registrationThere are many different styles of registration for many different types of printing. These deal with stone lithography, as used in fine arts printmaking.
T-barThis method, using small measured registration marks on both the stone and the paper, is very accurate and simple to do. The printer measures the exact size of the paper and the desired margins. Then marks are made at both ends of the sheet of paper, and corresponding marks (usually in the shape of a "T") are made on the stone. Then the printer matches the marks on the paper to those on the stone. This way many runs of different colors can be pulled exactly in line with one another, each of them measured from the same system of marks.
Pin-holeThis method involves laying the paper on the un-inked surface, and making a pin-hole through both the bottom and top of the paper, being careful to make a mark in the stone's surface. Then the locations of the holes are transferred to each sheet of paper to be printed. When printing, one should place pins in each hole of a sheet of paper, and lower it onto the inked stone, placing each pin in its respective hole in the stone. This method can ruin paper by creating holes. And if the holes get too large, they lose their function as registration devices.
Eye-ballingThis method relies solely on hand-eye coordination. The printer places the paper over the stone-image, measuring and judging registration by eye. This is not very consistent, depending on the person.
IMAGES OF CROP MARKS//REGISTRATION//REGISTRATION BLACK