Prompt #7: Opal

In this post, I'm going to discuss the use of coloured filters a bit more.

When you apply such a filter to a graphic, its effect is overall. However, although it modifies the hues of the coloured areas, white areas simply get a flat clean wash of the pure colour. This is how a new colour can be added to the graphic. For example, the following sequence shows how I turned a background tile in purple shades into a purple/yellow bicolour (that I included in the Amethyst post).



If you're curious, the colour was "cleaned up" by pushing the contrast a bit. Here are a few more examples:



A fair number of graphics shown in earlier posts use this technique, in combination with others. Eventually, I got the impression I'd pretty well done all I could with brown128.jpg and was basically just repeating myself. It was quite a while before it occurred to me that I could be a bit more creative in my use of filters.

In an earlier post, I described how I used contrastive colours to grey out part of the pattern. Given how long I've been playing with these graphics, I was a bit surprised to trace back through the collection and realize that it was less than two years ago that I thought of trying this. In fact, it was on 1 November 2020 that I took the first graphic in the set below and applied a red filter to counter the turquoise:



The result was intriguing, but not especially exciting in and of itself, though it did show potential for future development. I tried the same technique on a few other tiles with similar results: a sort of muddy muted greyish shade combined with bright "feathering".

The following day I went back and tweaked things, aiming for a true grey. This time, though, I came up with a truly startlingly gorgeous result:



And if, to your eyes, it's not startlingly gorgeous, then just remember (for I'm sure I've mentioned it!) that I'm particularly fond of the colour brown and related shades.

Of course, the first thing I did was hie off to GRSites.com and run it through their colour-wheel-rotation doohickey. This yielded such variants as these:



I explained back in Post #2 how further work paled the grey areas to pastel and off-white, with just enough shading remaining to give the pattern shape. You've seen the following examples before; but I'm repeating them for comparison purposes—both with the ones above and the results of later tweaking:



Using the technique described at the beginning of the post, a bicolour can be achieved with a fairly deeply saturated filter. Of course, it will somewhat influence the hue of the "feathers"; but it will also wash a contrastive colour over the pale areas:



However, if only a lightly saturated second filter is applied (perhaps with a touch of contrast), this can add complexity to the pale areas without washing the ground colour out entirely. In this context, it is important to remember that, when a coloured filter is applied to a graphic, its effect on areas where the colour is saturated, though real, is less obvious to the eye than its effect on pale areas.



The obvious next question, of course, is this: if filters can be used to produce a pale grey or beige (and then white), can one mute out the colour to a dark shade and thence to black?

The answer is ... sort of. If you look at even the variants above with the palest areas, they aren't pure white: more off-white with tinting, thus showing the pattern. Similarly, you don't really get true black, since there is always some residual colour in the pattern. Still, on 2 November 2020 (the same day I made the striking beige-toned one above), I also produced these:





Among the variants shown in earlier posts were some made using this technique. I repeat them—now in the context of their derivation—with a few more added for good measure:





You can lighten graphics like these (and then add variety with other filters); but there's a limit to how much you can darken them and still have definition. Basically, because computers use additive colours, the more you work with these graphics, the lighter they get.

And, of course, there is a next question. In this post, I've been showing what happens when contrastive filters are applied to the broad areas of the background tile. So what happens if you try applying such a filter to the "feathers"?





Previous Days:
Prompts #1 and #2 (Amber and Topaz)
Prompt #2 (Rose Quartz)
Prompt #3 (Garnet)
Prompts #3 and #4 (Moonstone and Hematite)
Prompt #4 (Kyanite)
Prompt #5 (Peridot)
Prompt #5 (Bloodstone)
Prompt #6 (Aquamarine)
Prompt #6 (Amethyst)
Prompt #7 (Sunshine Jasper)
Bonus #1 (Turquoise)
Bonus #2 (Smoky Quartz and Onyx)
Bonus #3 (Rubellite)
Prompt #7 (Opal) - Part One
Prompt #7 (Opal) - Part Two
Prompt #7 (Opal) - Part Two-and-a-half