Scanhancer intro
Models & details
Is this real?
Why 5LE?
Newton's rings
Scanhancer LEK
Other scanners
How to order?
User comments
Order now
Contact us

How do I avoid banding (streaks) in my scan?

Summer Polder kleinSome people experience banding in very even areas of their pictures, like blue sky, when scanning with the Scanhancer 5LE. This problem is caused by the scanner (NOT by unevenness of the Scanhancer), especially when it is not heated up well. The light source inside the Multi Pro (a very thin fluorecent tube light) gives a bit uneven light as long as it is cold. The CCD of the scanner auto-compensates for this unevenness during setup. The Scanhancer however evens out the light so well that this compensation becomes unnessesary. Unfortunately calibration is done without the Scanhancer in the light path, so the CCD will still compensate, thus causing 'compensating bands'. This can mostly be avoided by letting the scanner warm up for a sufficient amount of time, at least 20 minutes. After that the tube light is so evenly lit that it should not cause trouble anylonger. Before scanning after these 20 minutes, hit the CTRL(Apple)+SHIFT+i keys, so that the scanner will recalibrate to the heated light tube. This is also very advisable when not using the Scanhancer, because an initially compensated light source might look very different after scanning for about half an hour (MF, 16bit, 8x sampling, 4800dpi). In between there is no recalibration of the CCD, so slowly bands will show up during a 'cold' scan. I have seen this effect on several occasions.

Theoretically it is possible to still see some banding after proper pre-heating. This is due to permament unevenness in the light source. I would personally have it replaced if that would occur.

I have worked on some new solutions in order to fight the banding issue and also limit the loss of light by the Scanhancer. In case you are willing to open up your scanner and make some (simple) changes in there, download this manual. Please note that this service will only be supported for existing Scanhancer customers!

Users of VueScan can use the following method of calibration with the Scanhancer 5LE in the light path of the scanner. This method is for both 35mm and medium format:

1. Turn on the Multi Pro and allow it to properly heat up for at least 20 minutes.

2. After 20 minutes turn the scanner off and immediately on again, so that it will do a standard calibration to the heated condition.

3. Insert the Scanhancer 5LE to the medium format holder, but DO NOT insert film (yet). Any mask from 6x6 on or bigger will do. Leaving out a mask is also possible but beware of Newton's Rings between the surfaces then. Make sure that all surfaces are well cleaned!

4. Start up VueScan and choose Calibrate from the Device menu.

5. VueScan will prompt you to remove the film holder and to click 'Yes'. Don't! Instead of removing the holder, you insert the MF glassholder that you have prepared with the Scanhancer. Now click 'Yes'.

6. Vuescan will start its calibration process and automatically make adjustments to the Scanhanced light. When it is finished press the eject button and remove the medium format holder. You can now start to use the scanner to your liking with either 35mm or medium format.

For those experiencing micro-banding (one pixel wide coloured lines; not the problem described above) someone has posted a Photoshop plugin to fix it in this discussion. It seems to work only on a PC though. The direct link to the file: (56Kb).