On Thu, 13 Sep 2012, pol stra wrote:

>
>> Off-topic for this mailing list, but on-topic for you: You can do this
>> with Inkscape.
>>
>> * Install Inkscape: http://inkscape.org/download/?lang=en
>> * Open the EPS in Inkscape
>>
>> Working white-on-white sucks, so
>> * File > Document properties > click to the right of 'Background:',
>> below the Default units dropdown
>> * Choose something nice and pastel-coloured with alpha (opacity) set
>> to non-zero.
>>
>> * Select the object
>> * Object > Ungroup (Ctrl+Shift+G) to make Inkscape see the individual
>> paths, instead of a single EPS object
>> The single rectangle selecting the object has now turned into a heap
>> of rectangles.
>> * With the colours at the bottom, set the fill to be red with click
>> and/or set the stroke to be red with Shift+click
>>
>> This will probably not have the desired effect because some of the
>> constituent paths will have black fill+transparent stroke, and with
>> others it will be the other way round. So you'll have to set
>> fill/stroke individually.
>>
>> * Select paths in turn, and set their fill/stroke as appropriate.
>> Their respective values are shown in the bottom left. If you select
>> multiple paths and their fill/stroke is different, it will be shown as
>> "mixed"; when multiple paths' fills/strokes are not mixed they are
>> identical, and you can change them all at once.
>>
>> (Depending on ... file-related things ... you may need to use Path >
>> Object to Path at some point, and possibly Path > Break Apart. But
>> probably not.)
>>
>> Good luck!
>>
>> --Sietse
>
> Thanks Sietse
>
> I already tried the inskape way, but it’s too much work if you have many files to proced.
> But your answer gave me the idea to use imegemagick, so I found this trick:
> convert -background none -density 300 -negate a1.EPS bbb.png
> I do not know why, but the same command with an EPS output gives me a white background so I had use a png file.
> The result is good enough for me.

If you want to use eps images, why not just use a white background at 
ConTeXt end (as you had stated in your first message).

Aditya