Weird Yellow Color Artifact

I have been using NLP for a few month now. Most of the scans are very good. However I have been scanning some pictures i shot while away in Thailand and for a lot of the pictures i found out that the outcome of the scans have some yellowish shadow in them. I don’t see it in my negatives and the light source is not dirty. I realize that a lot of times this comes with picture with a very uniform look, i.e. a lot of skies, sea.
Does anyone knows what is the problem and how to fix it?
Thank you

Looks like it could be caused by reflections off the film when you’re digitising

I tried in a pitch black room , with both sides of the film… This problem doesn’t occur every time. It occurs mostly when every thing in the picture is similar (i.e. sky+sea). When that problem occur the picture is also way more contrasty than is should be.

You should check out this rundown of some of the numerous things these orange and yellow splotches when digitizing film with a digital camera:

There are a few steps you should take:

1. Make sure to mask at ALL the stray light from your light source. It doesn’t need to be fancy. Some dark construction paper with a mask cut out will do.
2. Be sure to use your lens hood
3. Take of any filters that are on your lens (like UV filters)
4. Shoot the emulsive (matte) side of film facing towards camera (it’s less reflective and less likely to catch the light reflecting back from your camera/lens).
5. Make sure your aperture is at f/8.0 to avoid lens vignetting.
6. Shoot manual and expose with your DSLR so that the negative is just right of center in preview histogram on camera. (If the digitization is extremely under-exposed, it could exacerbate unevenness issues during processing)

I’d also recommend the following:

1. It’s better to use a dedicated macro lens (without no extension tubes)
2. Modern macro lens have better lens coatings and flare protection, so less prone to this
3. Mirrorless cameras are more prone to sensor flare because the sensor is closer to the lens elements (Sony seems to be the worst)

Hope that helps!

Creator of Negative Lab Pro

thanks, i will check that rundown, let you know if the problem is solved.

what’s your light source?