See Similarity Maps for an explanation of similarity shading.
This page shows how the six similarity shading combinations impact the image of the day on 10/14/18. I will also explain how various adjustments I’ve made in the program impact the shading.
The Combinations
| # | Primary | Secondary | Category |
| 1 | Red | Blue | Magenta |
| 2 | Blue | Red | Magenta |
| 3 | Green | Blue | Cyan |
| 4 | Blue | Green | Cyan |
| 5 | Green | Red | Yellow |
| 6 | Red | Green | Yellow |
The primary color tends to be seen in areas with longer lines, while the secondary color is more common in areas with short lines. The primary color is usually more prominent in the image, though this is mostly a result of the adjustments I have made to the map.
Although I refer to both red/blue and blue/red as magenta shading, the individual combinations are often more similar to the red/green and blue/green respectively.
Seven Versions of One Image
Here is a link to the original, full-sized image,which is going to look a lot like one of the images below.
#1 – No Similarity Shading
#2 Red/Blue
#3 Blue/Red
#4 Green/Blue
#5 Blue/Green
#6 Green/Red
#7 Red/Green
The Shading Files
Here are the shading files for all six combinations on a black background (the background is transparent when they are overlaid on the lines):
Adjustments Made to the Shading Files
There are various settings in my program that I use to change the appearance of the shading files. I will use the combination blue/green to demonstrate this, since it is the one I used for the image of the day.
Here is what the shading file looks like based on the calculations shown on the Similarity Maps page without any adjustments:
and the resulting image:
Reducing the Shading
There are two adjustments that I make that make the shading less opaque prior to overlaying it on the image with the lines. Here is what the shading file looks like after these adjustments:
Brightening and Separating the Colors
The other two adjustments made prior to overlaying the shading result in more blue and green and less cyan:
The Contrast Adjustment
My program increases the contrast for the full image including the shading, which ends up reducing the impact of the shading (especially in the darker areas between the lines). Here is the image before the contrast adjustment:
and again, the final version:
and the link to the full-sized image.
The End of Page Notes that I Never Bother To Finish
I haven’t gotten to this yet.