image transparency rendering

[LivinLOS]

Graphics problem..

I am trying to sort out and finish a site for a mate.. The issue I am having is the sites color scheme is black / charcoal / orange (harley colors)..

When I have a black background and put a graphic with a transparency on it (as I must do for his logos, theres a white fuzz around the image as it renders the image on the black backgorund.. Looks ugle and ruins the image at small resolutions..

How do I set a transparency to work with a dark background color ??

Can see what I mean at www.V-TwinTours.com

[Nicke]

Usually you have a setting for Matte if you want to save with transparency, set matte as black or white or whatever background color you have. I think most image editing programs use white as default.

Originally Posted by LivinLOS

Graphics problem..

I am trying to sort out and finish a site for a mate.. The issue I am having is the sites color scheme is black / charcoal / orange (harley colors)..

When I have a black background and put a graphic with a transparency on it (as I must do for his logos, theres a white fuzz around the image as it renders the image on the black backgorund.. Looks ugle and ruins the image at small resolutions..

How do I set a transparency to work with a dark background color ??

Can see what I mean at www.V-TwinTours.com

[LivinLOS]

Done that in fireworks..

Still leaving a white outline.. Wonder if white is coded into the image somehow.. Shouldnt be as I made the 'white' the transparent color but perhaps its an off white due to the merging of pixels as it was resized..

[Nicke]

A quick fix would be to select all, reduce the selection with 1 pixel (or maybe 2) and you should get rid of the white/light pixels.

Or select by color and select all whites and/or light pixels and simply erase them.

[Tyfon]

Are you working in jpeg format at any point along the way? Or otherwise dithering colours?

When setting the palette transparency you can only nominate one entry as the transparent colour. If there is any jpeg (or other) compression or dithering in the image's origins then you will find that along a border between colours the compression 'smoothes' the edge a little so, for example, along a black and white border you get a layer of grey pixels. If you set your transparency to white then the grey pixels will not be transparent and you get a light (perceived as white) edge to black objects.

To eliminate this I took your graphic and put it in Paintshop Pro. I upper the colour resolution to 16 million and then used colour exchanger to alter all the white background pixels to blue (0,0,255) - a colour not in the original palette. Setting the colour exchanger's tolerance to 80 meant that the lighter shades of grey were aso changed to blue. Thecomplicating factor was that the image of the engine contained some white and light grey elements so I couldn't just universaly change all light greys to blue - I had to use the colour exchanger brush to skirt around the engine. Over the text I could just go mad. Eventually I upped the colur exchanger tolerance to 100 to eliminate all the greys around the text. That left me with a single unique colour (blue) to nominate as transparent which I did and saved as gif (below - put it on a black background and you'll see).

So, in summary, work only with uncompressed gifs and bitmaps with large palettes (they will be reduced when saving as the final gif) and no colour dithering. Use a striking colour not present elswhere in the image (pure blue is good for most occasions) to flood the background(s) and set this as your transparent colour.

Cheers,

K.