Poor image rendering with Google Docs PDF viewer

Question

I used Word 2007 to create a PDF file with an 1526px * 900px image filling a whole page. This is not the first time it's happened, but Google Docs PDF viewer absolutely mangles the colour rendering making it unusable.

I've taken screenshots at the same zoom level in Google Docs viewer and Foxit Reader.

Here's an image for comparison:

It's awful! I've tried messing about with some things, but can't find anything that can correct this issue.

Answer 1

Let it be recorded here, 16 months after the present original posting by Turkeyphant and a similar posting [1] on the Docs+Drive product forum, that the problem appears to have been fixed within about the past week. Since that time, when a pdf (or Word) file is opened that resides on the Docs+Drive cloud, the file is rendered with what appears to be proper 24-bit color. The treatment whereby the color was reduced to 5 bits, which could encode 32 colors or 32 shades of gray or 16 of each, depending on the image, has been abandoned.

To the best of my knowledge the Docs+Drive staff have not announced this change, either on their Blog or on their product forum. I noticed the change a few days ago and noted it on the conversation [1].

[1] (2013-05-21) Problem in pdf-viewer with color images https://productforums.google.com/d/msg/docs/_bdfiYgjF2s/5PDMdp9MhFQJ

Answer 2

In Chrome you can select "Print" and then "Save as PDF". The image quality in the saved PDF file will go up significantly, compared to the one from "Download as PDF". Google seems to be optimizing images to preserve bandwidth.

Answer 3

It might have something to do with compression of the image in the PDF.

I mean, PDF supports JPEG2000-encoded images (JPXDecode Filter) and PDF Reference states that:

From a single JPEG2000 data stream, multiple versions of an image may be decoded. These different versions form progressions along four degrees of freedom: sampling resolution, color depth, band, and location. For example, with a resolution progression, a thumbnail version of the image may be decoded from the data, followed by a sequence of other versions of the image, each with approximately four times as many samples (twice the width times twice the height) as the previous one. The last version is the full-resolution image.

Google Docs viewer might be displaying only first version of the image (with lower resolution or lower color depth) thus producing "awful" output.

Answer 4

Perhaps the attached pair of images will help towards clarifying what is happening with color in images that are rendered through the Google Docs pdf viewer. I inserted the Wikipedia image RGB_Color_Solid_Cube (1024*1024 pixels) into an otherwise empty Google Docs text document, converted it to pdf, and viewed the resulting pdf files two ways: once through the Google Docs+Drive pdf viewer and once through the regular pdf viewer of the Chrome or Firefox browser. Then I made screenshots. Here is the RGB Color Cube via the Docs PDF Viewer and here is the RGB Color Cube via a regular browser PDF Viewer.

The color resolution in the Docs PDF Viewer version is really awful; it looks like 64 colors at most. Maybe someone else is able to recognize this kind of rendering and identify the problem better.

Answer 5

This is related to compression and it's something that you can't change in the default view of Google Docs Viewer. The simple solution is to upload the PDF and just serve it from the site in an iFrame. Here is an example:

Problem Embedding Google Docs PDF Solution

Mike