Mask Detection and Scanner Alignment

To use the larger frame of the BOBACH 135 Full Frame Mask, the optical axis of your SP500 or SP3000 must be correctly centered and adjusted.
During initialization, the scanner needs to detect the mask reliably.
Because the Full Frame Mask uses a significantly larger opening than the original mask, correct alignment becomes more important.

If the scanner is slightly misaligned, the original mask may still work because its cutout/Frame is smaller. With the Full Frame Mask, however, even a slightly misaligned optical axis can cause the scanner to fail during mask detection and show the message “Detecting of the Mask failed.”

This guide explains how to check the alignment of your scanner before using the Full Frame Mask.

The pdf guides for setting the optical axis are at the end of this page.

If you see the "W-4426" or "W-4425" error after inserting the full-frame mask, the scanner's optical axis is misaligned.

The optical axis is the sensor's position in relation to the mask. For proper full-frame scans, the sensor must be precisely centered above the mask.


To check the optical axis of your scanner, open the "setup and Maintenance" menu and navigate to "04 Carrier Adjustment/Maintenance" -> "0420 Mask Position Adjustment".


Insert the original Fujifilm lower mask into the carrier, wait until the carrier has initialized, and click "image Disp".

The mask must appear perfectly centered and symmetrical in the preview image, with the surrounding borders being equally wide on the top, bottom, left, and right sides.

Adjusting the settings via the four arrow keys does NOT change the optical axis. The scanner needs to be opened to do that.

If the optical axis is not correctly adjusted, the mask will appear shifted in the preview image, meaning the scanner's sensor is not centered above the mask.

The scanner's service manual, in the section "Optical Axis Adjustment," explains how to correctly align the sensor.

The "focusing chart jig" described in the manual is not necessary correction can be performed by inserting the full-frame mask and adjusting based on its edges.


Once the optical axis has been correctly adjusted, the edges of the full-frame mask are the same on all four sides. Now, the scanner can detect the mask during initialization, and it can be used for scanning.