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<div class="moz-cite-prefix">[Just realised that the XeTeX list
should have been cc'd, so doing so now and will forward Paulo's
original images as attachments]<br>
<br>
Philip Taylor wrote:<br>
</div>
<blockquote type="cite"
cite="mid:3ea45983-1dea-a5e5-793d-83e35e30c1d2@Hellenic-Institute.Uk">
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<div class="moz-cite-prefix">Ulrike Fischer wrote:</div>
<blockquote type="cite" cite="mid:ujnndzz5luth.dlg@nililand.de">
<pre wrap="">I can't reproduce your problem with the files you provided.
How do you compile? Which TeX-System do you have? And which viewer
do you use to view the pdf? Can you provide the pdf you get?
</pre>
</blockquote>
<br>
For me (Windows 7 64-bit Enterprise, TeX Live 2020), PdfLaTeX does
<i>not</i> shew the problem whilst XeLaTeX does. The artifacts
are more visible in the TeXworks previewer than in Adobe Acrobat
CC, but are nonetheless visible in the latter.<br>
<br>
<i>Philip Taylor</i><br>
</blockquote>
<i>--------</i><br>
<blockquote type="cite">
<div class="moz-text-html" lang="x-unicode">
<div dir="ltr">I have (a couple) of PNG images with a background
color of, for example, RGB(80,64,83), that when placed on a
page of the same background color with {graphicx} -- they show
a distinct tonality against the background -- which is of the
same color.<br>
<br>
````<br>
\documentclass{report}<br>
<br>
\usepackage{xcolor}<br>
\definecolor{bgcolor}{RGB}{80,64,83}<br>
<br>
\usepackage{graphicx}<br>
\pagestyle{empty}<br>
<br>
\begin{document}<br>
<br>
\pagecolor{bgcolor}<br>
\includegraphics[width=0.5\textwidth]{A.png}<br>
\quad<br>
\includegraphics[width=0.5\textwidth]{B.png}<br>
<br>
\medskip<br>
<br>
\includegraphics[width=0.5\textwidth]{A-gimp.png}<br>
\quad<br>
\includegraphics[width=0.5\textwidth]{B-gimp.png}<br>
<br>
\end{document}<br>
````<br>
<br>
Checking the colors in the included files one can see they
have changed from (80,64,83) to (71,56,74) in the included
images.<br>
<br>
Just opening the images on `GIMP` and exporting it as-is with
the default choices of<br>
<br>
<img src="cid:part1.A3B2AA6D.73582F16@Hellenic-Institute.Uk"
alt="export-settings.png" height="412" width="341"><br>
<br>
fixes everything and the new inclusion now gets the exact
color they were set to begin with, the same as the background,
as shown below (second line).<br>
<br>
<br>
<img src="cid:part2.F61A10FD.8517D0CD@Hellenic-Institute.Uk"
alt="together.png" height="392" width="562"><br>
<br>
What is that TeX needs from the PNG's to preserve their color
when included in a page?
<div><br>
</div>
<div>Paulo Ney</div>
<div><br>
</div>
<div><br>
</div>
<div>PS. For experimentation here are the same images, before
and after opening with GIMP.<br>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
</div>
</div>
</div>
<br>
<fieldset class="mimeAttachmentHeader"><legend
class="mimeAttachmentHeaderName">B-gimp.png</legend></fieldset>
<div class="moz-attached-image-container"><img
class="moz-attached-image"
src="cid:part3.CB9CE9D8.1E619097@Hellenic-Institute.Uk"></div>
<br>
<fieldset class="mimeAttachmentHeader"><legend
class="mimeAttachmentHeaderName">A-gimp.png</legend></fieldset>
<div class="moz-attached-image-container"><img
class="moz-attached-image"
src="cid:part4.D5942233.123E56FB@Hellenic-Institute.Uk"></div>
<br>
<fieldset class="mimeAttachmentHeader"><legend
class="mimeAttachmentHeaderName">B.png</legend></fieldset>
<div class="moz-attached-image-container"><img
class="moz-attached-image"
src="cid:part5.8694A2C2.0AA90CDC@Hellenic-Institute.Uk"></div>
<br>
<fieldset class="mimeAttachmentHeader"><legend
class="mimeAttachmentHeaderName">A.png</legend></fieldset>
<div class="moz-attached-image-container"><img
class="moz-attached-image"
src="cid:part6.67A45A80.3B281500@Hellenic-Institute.Uk"></div>
</blockquote>
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