I am contemplating making 4x5 test targets for those who scan 😏.  Not even sure if there is any demand for that.  Anyway here is couple of prototypes I came up with . The idea for second design is to support multiple shots and stitching process.  Please let me know if you think this is needed, also design /layout considerations will be appreciated. Positive and negative targets will be available ( if folks decide it's worth the effort).

Here is more details on new Type 120 Positive Test Target PO69. This is exact reversal of the Negative Test Target NG69.   The note from Vlad:  The reasons why I started offering the Positive Test Targets are as follows. Everyone who used negative targets while viewing images in the digital camera have encountered the strong hallo around target's bars and stars. That's because camera sensor averages the brightness of the scene and sets certain exposure values. Given that most of the image is almost black (in case of negative) the camera brings brightness up until black areas look gray. That means that transparent areas with bars and numbers are getting overexposed (they basically end up being in Zone 0) . That forces operator to manually step down camera to avoid those overexposures .  Still the halos remain the issue and interfere with the focusing. With positive targets the i ssue will go away - the sensor reads mostly transparent areas, the averaging will lead to...

  Just for the reference, if anyone is wondering how much horizontal setup might cost, here are my numbers (certain pieces like camera and lens are bought as refurbished items so they may cost more or less depending on the source). I am ready to discuss the given choices if anyone cares to ask in the  comments. Part description Cost US$ URL (Vintage) Canon slide dublicator $50 https://beta.kamerastore.com/products/canon-slide-duplicator-14 ...