Holga is a preset that you can use in Silver Efex and that gives the photo an old look with the typical pinhole effect of the earlier cameras of this brand. By adjusting the curve, the whites become whiter than white so that they appear to glow. I made the preset to give an old look to the photo with a lot of grain, but of course it can also be used for other purposes, you can try that yourself (I haven't done that yet). When using this preset I add a lot of accents in the middle of the photo as is typical for Holga cameras. You can download the preset below. Install it in Silver Efex. At the bottom of this article is a link to a brief instruction how to install presets.
An example of the before and after situation: