What is the best general image type and settings for pics?

With the release of TNT v. 2.0 the EC Software screenshot program has become a serious application in its own right, so it was high time that it was given its own forum!

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RaymondS
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What is the best general image type and settings for pics?

Unread post by RaymondS »

I read through the very informative post on this (http://helpman.it-authoring.com/viewtopic.php?t=4228) but I have to admit that I am still a bit lost as to what I should use...

For very standard screenshots of just normal Windows apps, what do I want to save them in BMP, JPG, GIF, or PNG?

About 95% of my use is to create a quick PDF for mini-user's manual - so I use my snapshots in H&M and use the standard_manual_short template. The other 5% of my time is to create actual help (chm) files.

I notice that the built-in screen-capture tool in H&M saves to JPG, but since I am now thinking about using TNT I can choose what is "best" for my case... I just don't know what "best" is!!!! :-)

Also, what color depth???? - there are quite a few options there as well!

Thanks for any feedback!
-Raymond
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Tim Green
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Unread post by Tim Green »

Hi Raymond,

The capture tool can save in multiple formats, it just remembers the last format you saved in, you can always change it before saving.

Generally, the most practical format to use in Help & Manual is BMP, combined with the setting 256-colors to GIF and TrueColor to JPG in your HTML export options. BMP is the best basic format, because it is lossless and can be converted best to all other formats. Also, PDF only understands BMP anyway, so there no conversion is needed (you can apply additional JPEG compression in your PDF publishing options if you want to further reduce image size, but this will reduce quality).

As a rule of thumb, save to BMP with 256 colors for screenshots and use more colors than that only for screenshots that don't look good in 256 colors or for photographs and other continuous tone images.

In most cases these settings will produce the smallest possible output files with the best quality with minimum fuss and bother. 8)
Regards,
Tim (EC Software Documentation & User Support)

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RaymondS
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Unread post by RaymondS »

Tim,

Thank you!!! That was EXACTLY what I wanted/needed!

I will make the necessary settings!

Thanks again,
-Raymond
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Winsteps
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Unread post by Winsteps »

Tim,

BMP is wonderful but huge! For example, 695KB for a BMP, 31KB for the same PNG.

Even with modern technology, this is a big difference in terms of emailing, back-up, download, etc.

Tim - what picture format do you recommend for small loss and small size as input into H&M?
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Tim Green
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Unread post by Tim Green »

Winsteps wrote:BMP is wonderful but huge! For example, 695KB for a BMP, 31KB for the same PNG.
Modern hard disks are so big and so cheap that this should have stopped being a problem several years ago. You can now get a terabyte drive for $70. However, if you regularly need to mail your source images you can use PNG or GIF (PNG is generally better) for images with up to 256 colors and JPEG for TrueColor images. However, these will all have to be converted to BMP when you compile to PDF.

Important: Never use PNG for images with more than 256 colors. PNG is only efficient with indexed colors up to 256, with full-color images it is huge, only marginally smaller than BMP.
Regards,
Tim (EC Software Documentation & User Support)

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Winsteps
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Unread post by Winsteps »

Thanks, Tim. You must have advised using PNGs before, because that is what I now use.

BTW, how long does it take to back-up a terabyte drive and onto what media? Currently my gigabyte back-ups are on DVDs.
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Martin Wynne
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Unread post by Martin Wynne »

Winsteps wrote:BMP is wonderful but huge! For example, 695KB for a BMP, 31KB for the same PNG.
Hi,

BMP with normal encoding is indeed huge. However, for screenshots and computer graphics you can normally select the lossless run-length encoding option instead (RLE encoding) when saving BMP files. BMP files with RLE encoding are a fraction of the size of normally encoded BMP files, unless used for "photographic" images.

But not as small as 256-colour PNGs which is my preferred option for saving screenshots. Unlike BMP they can be attached to an email or included in a web page when needed without further processing.

For the graphics image below:

Normally encoded 256-colour BMP: 230KB

RLE encoded 256-colour BMP: 50KB

256-colour PNG: 19KB

JPG with minimum compression: 90KB

regards,

Martin.
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Winsteps
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Unread post by Winsteps »

Great idea, Martin.

Tim: Can H&M or TNT process BMP-RLE? If not, how about adding that option?
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Martin Wynne
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Unread post by Martin Wynne »

Winsteps wrote:Can H&M or TNT process BMP-RLE?
Hi,

Like many graphics programs, EC softwares (H&M, Impict and TNT) don't have an option to save in 8-bit BMP-RLE format. (Or if they do, I haven't found it :( ).

But they can open and use such files, as can almost all software which can open Windows BMP files.

RLE is defined only for 8-bit, 256 colour, bitmaps (and fewer bit depths), so it is usually necessary to select 8-bit, 256 colour, BMP in order to see the RLE compression option in software. Programs which I have used and can save in 8-bit BMP-RLE:

PaintShopPro (which also makes excellent screen captures and is a great tool for colour-depth reduction to 8-bit, 256-colour, even on many photographic images).

The excellent AnyImage batch converter. ( http://www.fmjsoft.com/anyimage.html )

Serif Photo Plus -- not the best graphics editor, but a free version is available from http://www.freeserifsoftware.com (70MB download!). Use Export (not Save As) for BMP, select 8-bit and RLE compression in the "Optimizer".

Having said all that, I still think 8-bit PNG is the best all-round format for saving screenshots. H&M happily converts them to bitmaps before using them in the PDF output. PNG files are normally saved with zero compression and lossless, so when compiling PDF there is no difference internally between an image loaded in 8-bit PNG format and one loaded as 8-bit BMP. PNG takes a fraction longer to decode, but on the other hand the much smaller file reads in faster.

regards,

Martin.
RaymondS
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Unread post by RaymondS »

This thread has been very helpful!!!

OK, I too have to admit that I still like to keep my files as small as possible... even if the hard-drives are bigger...

So, I have to ask... if I do save my screen-shots to PNG, I understand that during my PDF creation the PNG has to be converted back to BMP and then to whatever format is used by the PDF engine to create the PFD file...

So it may take a bit longer (that;s ok) but is there any "down-side" on double conversion?

I remember back a year (or two) when I noticed that some of my screen shots had some funky colors!!!... I posted some question here at that time... but I am pretty sure that I was saving my screen-shots then as JPG... I just do not want to run into the "funky-color" problem again!!!

If I can save as PNG and save space and be assured that I will not have funky colors in my snap shots, GROOVY... otherwise, I guess I will have to stick with saving as "chunky" BMP's.

Thanks for your input,
-Raymond
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Martin Wynne
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Unread post by Martin Wynne »

RaymondS wrote:So, I have to ask... if I do save my screen-shots to PNG, I understand that during my PDF creation the PNG has to be converted back to BMP and then to whatever format is used by the PDF engine to create the PFD file...

So it may take a bit longer (that;s ok) but is there any "down-side" on double conversion?
Hi Raymond,

There is in effect a "double conversion" regardless of which file format you use. Image files after loading into memory aren't in any file format, they are stored in an internal format -- for H&M that is probably either TBitmap or TBitmap32 -- see:

http://graphics32.org/documentation/Doc ... /_Body.htm

Image files on loading are converted to that internal format, and then on writing to a PDF file they are converted back to the required PDF file format.

So if you save images in any lossless format -- BMP, GIF (8-bit only), PNG with zero compression -- the end result in memory will be the same, for the same original image/colour depth. And the PDF output will be the same.

For the HTML-based outputs from H&M, the files aren't loaded into memory if they are GIF, PNG or JPG, they are sent as-is to the output web pages.

Funky colours depend on which software you use to reduce screenshots to 256 colours (8-bit colour depth) to shrink the file size, and which options you select for the reduction method. It's important to do that for the HTML-based output formats to minimize page load times. My experience is that best colour-reduction is done with PaintShopPro or AnyImage, rather than leaving it to H&M to do it.

However, if you are creating only PDF output, it is better to leave them as full-colour screenshots. The PDF format supports only full-colour images (using JPG format within the file), so there is no advantage in using only 256 colours for the input images -- other than smaller files on your own system.

regards,

Martin.
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