The overall strip marking allows users to set up their scanning rig precisely to capture the desired frame.

The test strip features a 50% raster that covers the entire strip.

This raster is made up of transparent and opaque squares with extremely high edge contrast (acutance). While the human eye sees the grid as a uniform gray tone, a camera can easily resolve the individual squares. Examining the shape and sharpness of these squares on a computer screen reveals key details about the scanning setup. Users can quickly assess whether the image is sharp and whether sharpness changes between the center, edges, or corners of the frame.

Here’s an example of how the image might appear if a corner is out of focus:

You can also use the target to check for even illumination and light fall-off.

1. Place the strip in the film holder, making sure it’s centered using the alignment markings on both the strip and the holder’s opening.

2. Turn on the camera and observe the live view. If your camera supports focus peaking, enable it to help with focusing.

3. Adjust focus by moving the camera up and down or fine-tuning the lens until you capture the part of the image you’re interested in. The printed markings make it easy to see exactly what will be captured and whether the holder is positioned correctly.

4. Take the shot. Tethered capture is strongly recommended—it helps avoid camera shake and speeds up image transfer to your computer.

5. Open the image on your computer and examine it at 100% magnification using any software with sharpening turned off. Start by checking the center of the frame.

6. If the center isn’t sharp and clear, refocus and fine-tune your exposure until it looks perfect.

7. If the center appears smudged, it usually means the shutter speed was too slow to freeze the image or your setup is experiencing vibration. Address those issues and try again.

8. Once the grid in the center is sharp and contrasty, check the edges and corners of the frame to evaluate uniform sharpness and detect any fall-off.

If one side or corner of the frame appears noticeably less sharp than the others, it’s likely due to misalignment between the camera sensor and the film plane. In this case, adjust the position of the camera or film holder until all corners and edges reach similar sharpness.

If the sharpness is even across the frame but still falls short compared to the center, the issue may lie with the lens. Try shooting at different aperture settings—most lenses deliver optimal performance around f/8, give or take a stop. If sharpness doesn’t improve, consider testing with a different lens.

Once the image is uniformly sharp from corner to corner, you’ve completed the most complex and time-consuming part of setting up your scanning rig. You can now replace the test target with your actual film and begin scanning.

Lighting issues can still interfere with quality, even if the color temperature is correct. Uneven illumination of the film introduces problems of its own. The principle here goes back more than 130 years to Max Levy’s halftone screening technique, which broke continuous-tone photographs into a grid of dots for easier reproduction in print.

We apply the same idea: the fine raster grid in the test target can reveal brightness and sharpness variations across the frame. To make these issues visible, open the captured image of the raster in software like Lightroom or Photoshop. Then apply a strong contrast curve using the Levels or Curves tool to exaggerate brightness differences. This will highlight any inconsistency in illumination or focus from one square to the next.

Once highlights and midtones are suppressed, brightness differences between the grid elements become much easier to spot. In the brightest areas, light can bleed from surrounding elements into darker ones—causing black squares to appear smaller. This visual effect reveals zones of higher brightness.

The operator should adjust the backlight to even out illumination across the entire frame. Uneven lighting is one of the most common causes of color casts and strange hues when negatives are inverted—especially if the light isn’t consistent from corner to corner.

Also, pay close attention to the edges of the film holder. Shadows and light scattering near the holder’s border can affect adjacent areas of the film. Take steps to minimize these effects with proper masking, baffling, or diffuser placement.

Q&A

Q: Do I need both a "35 mm alignment strip" and a 35 mm test target with USAF 1951 patterns, or can I use just one?

A: If you're looking to measure the resolution of your scanning rig in lines per millimeter (lp/mm), Vlad's Test Targets with USAF 1951 patterns are the right choice. They let you quantify resolution across the frame—comparing center to corners, or testing different lenses.

If you're not concerned with precise lp/mm values and prefer to assess sharpness by eye, the alignment strip alone will do. It also helps evaluate backlight uniformity, which is crucial for consistent image quality. 

Q: The alignment strip doesn't have actual perforations (sprocket holes). How does that affect film holders with drives for 35 mm film? 

A: While it's true that there are no real perforations, the strips have been tested with VALOI Advancer and Digitaliza+ drives. However, I cannot confirm which holders require perforations to advance film.

Q: Do Type 120 and 4x5 Vlad's Test Targets have the features described above? 

A: Yes, they do! Type 120 and 4x5 Vlad's Test Targets are made using the same laser technology and media. They feature a raster covering almost all areas between USAF 1951 targets, allowing for the same techniques described above.