Transparent Background - Why can't I?

[handrawn]

and no issues with creating alpha bitmap copies, unlike 'stained glass'

.. mind you I might have spoke too soon on that one ........

[molucca]

Steve,

Once you have a transparent bitmap, I believe you can set contone light and dark to black eliminating any transition shades.

Rich

[angelize]

Just out of curiosity Steve, what issues do find with creating a bitmap copy of a photo object or any object for that matter with Stained Glass Transparency? I have not had any problems with it and actually find it quite useful at times.

[xsnoopx]

Thank..you..for..sharing..this..information.

[handrawn]

Steve,

Once you have a transparent bitmap, I believe you can set contone light and dark to black eliminating any transition shades.

Rich

yes that works as a 'quick fix' Rich - thanks

[handrawn]

Just out of curiosity Steve, what issues do find with creating a bitmap copy of a photo object or any object for that matter with Stained Glass Transparency? I have not had any problems with it and actually find it quite useful at times.

ok from the top ...

stained glass, as stated in xara documentation, is a 'subtractive process' in RGB colour space

in a subtractive process you take one thing away from another

so when you apply a stained glass effect to object A, which has object B below it, then where they overlap you get a subtractive colour change: the result of subtracting the colour values in RGB space [which might actually result in 'no change' it is worth noting]

this is fine if the top object, the one with the stained glass applied, is totally underpinned by other object[s] - if it is not, if there is an area below the stained glass that has no object, then you have to start being careful - by definition, if you apply a stained glass effect to just one object [to remove white] this second case is going to apply

in fact of course even if there is no object below - there is always either the page area or the pasteboard and so the screen render is made on that basis

make a true colour bitmap copy and it is flattened, so effectively, the program inserts an underlying white object, and this is one of those cases where the result is 'no change' - no problem

make a + alpha bitmap copy and the filter has to make its own assessment of how to resolve the subtraction and you get a colour shift....... and in the case of the attachment it's time to call the vet

[there are some other minor issues - such as you can't select 'through' the stained glass transparent area without messing with the alt key - but the colour shift is the main one]