Pure white with the multiply effect should cause no change in the color of the pixels. If you use non-pure colors for your shadow sheet, your results will look very different that you might expect. This is because the red, green, and blue channels of the image are treated separately and any intuition you may have about colors is unlikely to apply to the case of RGB multiplication except for the case where at least one of the colors is purely desaturated (that is, a pure gray shade).
The idea of test cards is a good one, but the results vary wildly according to the source color images. As mentioned above, multiplying two color images together gives fairly unpredictable results; other filters can be even worse.
The Blend Mode effect should be fairly close to the blend modes in Photoshop (at least that was the intent). Searching the internet for terms like "Photoshop blend modes explained" turns up a number of useful and even somewhat applicable, if you ignore shortcuts and Photoshop-specific features).
Posted By: JimPI would go with Allyn's suggstion to me years ago and use pngs. Took me a long while to change my Crestar site to pngs, but it was worth it.
A 2MB file for a quick example isn't necessary. If I were trying to go for accuracy (e.g. on a color card), then I would be more willing to waste people's bandwidth and server storage on detail.
When I have finished Merelan City and Merelan Observatory, I would like to do a sort of "test card map", only it won't be a map. I'm scratching my head over the type of base image I should use to effectively demonstrate all the blend modes in strips across the page. I think it should be colour, but what colours. Just stripes would be very boring and also quite jiggly on the eyes. Has anyone got a good test card image that shows a good range of contrast in colour and tone over a large area that I could use as the background to such a test?
Ok. I still have a problem, but its not the edge fade.
Well, it is and it isn't. If you bear with me I will upload two images in quick succession on this one post.
I was trying to do a bit of relief shading on Merelan City by adding a sheet called SHADOW1 and using a blend mode and edge blur to add dark shapes where I felt the island would be in shadow (given that my sun is in the south).
I was pretty pleased overall with the effect, until I noticed the transparency acne around the cottages to the south of the current extent of the built up area. These images show what the same screen shot looks like with and without the cottages.
I tried every last one of the blend modes available and all different kinds of transparency, but nothing worked.
I think there's just something about that particular set of symbols (CD3 native bitmap 1 thatched cottages) that disturbs the blend mode effect, because if you look at the Vintyri houses (also in the shadow) you can see they are perfectly happy with the shadow and have no argument with it whatsoever.
I'm going to have to swap the cottages out for something else that doesn't disagree so much, because I want to finish the city, and I think it looks much better with the shadow than without it, but in the long run I would really like to know why these particular symbols are so stubborn about cooperating this way, or I might not be able to use them again for anything.
I think I may have found a workaround for the problem with the symbols that won't behave themselves.
I put a transparency of just 1% (99% solid) on the sheet where the buildings were, and it worked
Unfortunately I will now have to paste them all back again, because I don't want to have to go back to the last version of the file and have to do all the relief shading all over again!
The usual problem with halos around objects that won't cooperate with the effects system is that the objects in question are antialiased (that is, they have a smooth transition in opacity rather than an abrupt one). The CC3 effects system determines transparency by checking for any change at all: any pixels in the smooth transition will be treated as fully opaque rather than partially opaque). The technospeak for this is that CC3 uses image differencing to create a 1-bit alpha channel rather than using full destination alpha during rendering. The only fix for this involves changing how the rendering engine works internally and that comes under the heading of the major changes described elsewhere.
Using a shadow sheet with blur rather than an edge fade reduces the issue because the edge fade uses a distance transform to determine how things fade (the farther from the edge, the more opaque) and this distance transform is very sensitive to the shape of things. The blur technique, on the other hand, just smears things out and is fairly insensitive to the shape of things.
Comments
I notice how the multiply has kind of erased things under the white circles. That may make it a bit difficult to use.
The idea of test cards is a good one, but the results vary wildly according to the source color images. As mentioned above, multiplying two color images together gives fairly unpredictable results; other filters can be even worse.
The Blend Mode effect should be fairly close to the blend modes in Photoshop (at least that was the intent). Searching the internet for terms like "Photoshop blend modes explained" turns up a number of useful and even somewhat applicable, if you ignore shortcuts and Photoshop-specific features).
Well, it is and it isn't. If you bear with me I will upload two images in quick succession on this one post.
I was trying to do a bit of relief shading on Merelan City by adding a sheet called SHADOW1 and using a blend mode and edge blur to add dark shapes where I felt the island would be in shadow (given that my sun is in the south).
I was pretty pleased overall with the effect, until I noticed the transparency acne around the cottages to the south of the current extent of the built up area. These images show what the same screen shot looks like with and without the cottages.
I tried every last one of the blend modes available and all different kinds of transparency, but nothing worked.
I think there's just something about that particular set of symbols (CD3 native bitmap 1 thatched cottages) that disturbs the blend mode effect, because if you look at the Vintyri houses (also in the shadow) you can see they are perfectly happy with the shadow and have no argument with it whatsoever.
I'm going to have to swap the cottages out for something else that doesn't disagree so much, because I want to finish the city, and I think it looks much better with the shadow than without it, but in the long run I would really like to know why these particular symbols are so stubborn about cooperating this way, or I might not be able to use them again for anything.
I put a transparency of just 1% (99% solid) on the sheet where the buildings were, and it worked
Unfortunately I will now have to paste them all back again, because I don't want to have to go back to the last version of the file and have to do all the relief shading all over again!
Using a shadow sheet with blur rather than an edge fade reduces the issue because the edge fade uses a distance transform to determine how things fade (the farther from the edge, the more opaque) and this distance transform is very sensitive to the shape of things. The blur technique, on the other hand, just smears things out and is fairly insensitive to the shape of things.
I think I will go and quietly collapse in a corner somewhere now - having wasted the day by being an idiot!
Thanks Joe