This is the draft of an article, it is incomplete or in-progress.
You can help by contributing to missing sections, editing existing material, or helping to migrate this page from linked sources.
Elongation shrinkage: Difference between revisions
Robertbaxter (talk | contribs) No edit summary |
Robertbaxter (talk | contribs) No edit summary |
||
| (One intermediate revision by the same user not shown) | |||
| Line 10: | Line 10: | ||
# The speed of the '''scanner head''' (when scanning)—if the head moves too fast, the image will be shrunk; if it is too slow, it will be elongated. This is a more stable setting, so it rarely needs calibration (and should only be calibrated ''after'' correcting elongation/shrinkage in the write roller). | # The speed of the '''scanner head''' (when scanning)—if the head moves too fast, the image will be shrunk; if it is too slow, it will be elongated. This is a more stable setting, so it rarely needs calibration (and should only be calibrated ''after'' correcting elongation/shrinkage in the write roller). | ||
== Overview == | |||
== | |||
Calibration can be performed if the dimensions of the printed image do not match the dimensions of the original (this is often measured between [[Registration marks|registration]] or [[crop marks]]). What needs to be calibrated depends on how the machine is used on a regular basis. | Calibration can be performed if the dimensions of the printed image do not match the dimensions of the original (this is often measured between [[Registration marks|registration]] or [[crop marks]]). What needs to be calibrated depends on how the machine is used on a regular basis. | ||
* If the stencils are made ''both from the scanner bed and sending files from a computer'' then <u>both the write roller speed and scanner head need to be calibrated | * If the stencils are made ''both from the scanner bed and sending files from a computer'' then <u>both the write roller speed and scanner head</u> need to be calibrated. | ||
* If either the scanner bed is used ''exclusively'' or files are sent from a computer ''exclusively'', then <u>only the write roller speed</u> needs calibration (though both can be calibrated if desired). | * If either the scanner bed is used ''exclusively'' or files are sent from a computer ''exclusively'', then <u>only the write roller speed</u> needs calibration (though both can be calibrated if desired). | ||
On older and lower model-number machines however, pursuing perfect calibration can be a wild goose chase. It's only really necessary when miscalibration is detected between layers, or when perfect scale to the sheet is needed (to match fold lines, for example—as in a [[magic zine]]). | On older and lower model-number machines however, pursuing perfect calibration can be a wild goose chase. It's only really necessary when miscalibration is detected between layers, or when perfect scale to the sheet is needed (to match fold lines, for example—as in a [[magic zine]]). | ||
== Calibration procedure == | |||
Both calibrations can be made by comparing a <u>measured</u> (printed) distance against a <u>goal</u> (original) distance, along the left/right axis of printing (along the feed direction of the paper). | |||
{{DISPLAYTITLE:Elongation/shrinkage}} | {{DISPLAYTITLE:Elongation/shrinkage}} | ||
Latest revision as of 15:53, 26 September 2025
| Elongation shrinkage | |
|---|---|
| Difficulty | Beginner |
| Duration | 10 min. |
Based on the way stencils are made in the risograph, if certain test modes are not properly calibrated, printed images can be elongated or shrunk by 0–3 mm. This comes from two places:
- The speed of the write roller when making a stencil—if it is faster than it should be, the image will be elongated; if it is slower, it will be shrunk. This is a physical property of the changing properties of the depleting stencil roll (so it changes over time, based on how many stencils remain on the roll). On two-drum machines and full-featured one-drum machines, compensation for this often happens automatically, but on older and lower model-number machines, this will regularly need to be calibrated for 1:1 printing.
- The speed of the scanner head (when scanning)—if the head moves too fast, the image will be shrunk; if it is too slow, it will be elongated. This is a more stable setting, so it rarely needs calibration (and should only be calibrated after correcting elongation/shrinkage in the write roller).
Overview
Calibration can be performed if the dimensions of the printed image do not match the dimensions of the original (this is often measured between registration or crop marks). What needs to be calibrated depends on how the machine is used on a regular basis.
- If the stencils are made both from the scanner bed and sending files from a computer then both the write roller speed and scanner head need to be calibrated.
- If either the scanner bed is used exclusively or files are sent from a computer exclusively, then only the write roller speed needs calibration (though both can be calibrated if desired).
On older and lower model-number machines however, pursuing perfect calibration can be a wild goose chase. It's only really necessary when miscalibration is detected between layers, or when perfect scale to the sheet is needed (to match fold lines, for example—as in a magic zine).
Calibration procedure
Both calibrations can be made by comparing a measured (printed) distance against a goal (original) distance, along the left/right axis of printing (along the feed direction of the paper).