Grottos are caves. Their interiors are darker than their openings. Below is an example of a real grotto:
We can simulate the effect of looking into a cave or grotto by using the Composite tool at Image Magick. Below is the title image before annotating:
- Input image into any Image Magick. Write down its dimensions. (417x289) Also paste its url into your Find key.
- Click on the Resize tab. Resize image to 125% or more. (I used 130%)
- Click on Composite tab.
- Paste url of image into the box. Set Gravity to Center.
- Choose "Out" or "Xor" from the drop down menu. Click on the Composite button. There will be a big black rectangle in the center of the image.
Result
- Click on Composite tab again. Leave everything the same, except for the drop down menu. Choose Displace. Click on Composite button.
- Repeat the above step once or twice more. Look at your image. You want the fringing to appear on all sides of the black rectangle. If it doesn't appear on one or two sides, then do the following.
- Click on the Transform tab. Choose Flip. Click on the Transform button. Repeat and choose Flop.
- Click on the Composite tab. Leave all the same. Click on the Composite button. These steps are probably necessary to get the fringing on all 4 sides of most images.
- Repeat the Transform Flip and Flop steps.
- Go back to Resize and change the numbers to the original image size.
Result
- Click on Composite tab.
- Choose Threshold from the drop down menu. Click on Composite button.
Result
- Optional: If you want some speckly texture in the image:
- Click on Colormap tab.
- Change number of colors to 40 or less (not less than 10). Leave everything else as is.
- Click on the Quantize button.
This works only with some images.
- Finish image as desired.
ADDITIONAL EXAMPLES
Negating before the final composite gives the effect of looking at the outside from inside the grotto, if the border is dark. This border, tho, is light enough to show details, so it also acts as a frame.
| Deer & Ducks |
Deer & Ducks |
| Original |
Negate before comps |
Another negate.
| Original no longer available |
Colt |
| Original |
Negate before comps |
|
