best image formats and resolutions 4 screen presentation?

[hommealone]

Hi I'm a newcomer to Impress, so please excuse me if these questions are very basic, but I've been searching around for the answers in the documentation and haven't found the answers I need.

For preparing a slideshow of hand-drawn illustrations for presentation on screen using a computer and projector, I'm not sure which file-types are OK to use, and what image resolutions make the most sense.

The image files currently exist as (rather large) .psd Photoshop images. I am able to insert these images into the slides, but I am:
- afraid that the total file size of the presentation may become unmanageable;
- don't know if it will be possible to show the presentation using a computer which doesn't have Photoshop installed;
- don't know if the images will look fuzzier than need be due to showing 300 dpi native resolution files at 72 dpi screen(projection) resolution.

What are the implications of using the files "as is"?
Would I be better off converting each file to a jpeg image at 72 dpi?
If so, what are optimum sizes (length, width) for use in this type of presentation? Will that depend on the monitor resolution settings of the computer used to make the presentation? And what if I don't know that ahead of time?

If I DO indeed need to convert all of the image files,
I found a reference to the Sun Presentation Minimizer add-on for Impress (http://extensions.services.openoffice.o ... nMinimizer) and wonder if this might be a tool I could use to batch process the images from within Impress, rather than doing so manually beforehand, one image at a time using Photoshop, for example. Anyone have any experience with this?

Any advise greatly appreciated!

Many thanks,
- Paul

[Phil]

Hi and welcome to the community!

I am able to insert these images into the slides, but I am:
- afraid that the total file size of the presentation may become unmanageable;
- don't know if it will be possible to show the presentation using a computer which doesn't have Photoshop installed;

I think you can prevent both problems if you use copy the images via the clipboard from Photoshop and use Edit > Paste Special in OpenOffice to make sure they are pasted in Bitmap format.
Alternatively, you could indeed export the images to JPEG files, but I would recommend not to resample them. This would probably lead to even smaller file sizes in the presentation files .odp compared to using Edit > Paste Special, as OpenOffice internally uses the PNG format which does not feature a lossy compression like JPEG does.

- don't know if the images will look fuzzier than need be due to showing 300 dpi native resolution files at 72 dpi screen(projection) resolution.

You may resize the images anyway, so the images will have to be resampled by Impress anyway. Therefore I would not resample the images before pasting them (unless the resolution is very high).
This is in line with the comment you also made:

Will that depend on the monitor resolution settings of the computer used to make the presentation? And what if I don't know that ahead of time?

However concerning resampling in Impress when running the presentation, we come to one of its major flaws: The missing antialiasing features.
Therefore I often show Impress presentations as exported PDF in Acrobat Reader instead of using Impress itself, as graphics are rendered much better then.
Additionally, KeyJnote can be used, which is really a great tool for presentations!

I found a reference to the Sun Presentation Minimizer add-on for Impress (http://extensions.services.openoffice.o ... nMinimizer) and wonder if this might be a tool I could use to batch process the images from within Impress, rather than doing so manually beforehand, one image at a time using Photoshop, for example.

Yes, you could use the tool to minimize the file size of the presentation. However, if you have 300 dpi source files, I would expect that there is not much effect when using the tool.
Also, I think the tool would not work if the objects were Photoshop elements. So you need to do Paste Special or JPEG conversion beforehand anyway.
But I admit I don't have much experience with the tool. Maybe other people can add some of their experience.

HTH!

KR, phil

[hommealone]

Phil,

That helps a lot! Thanks very much for your very thorough and informative response.

Your link to the post about anti-aliasing problems especially helped alert me to issues I would otherwise have likely found out the hard way! The KeyJnote application is intriguing, though I have a few concerns about it.

For one thing, I don't know how easy/difficult it might be to use for a non-programmer, windows only, no command-line-stuff type? Couldn't quite tell from the documentation... Thoughts?

The recommended helper application - KeyJnoteGUI - seems only installable by a programmer type, for example (which seems odd for an application intended to keep people from having to use command-line etc., no?). But it might well not be needed at all.

More importantly, it seems like the presentation would need to be made using a computer with KeyJnote pre-installed, which could be a problem. Unless it can be installed on a USB drive?? (Have to check into that; do you know the answer to that? No forum on the KeyJnote site, unfortunately. Seems like an ideal candidate for a program to be made into a PortableApp program, though, doesn't it?)

Otherwise I'll look into your 'save-as-PDF, show using Adobe reader' method, or another alternative suggested in the post you recommended, 'save as .ppt, and to use the free MS PowerPoint viewer' option.

At least now I have a good idea of which formats and resolutions the images should be in to start with!

Any further pearls of wisdom always appreciated, but not required; you've been a big help already.

- Paul

[Phil]

Hi,

you're welcome - I'm glad I could help you!

I admit KeyJnote is a bit puzzling at the beginning.

However, it is very simple to use if you only need its basic functionality (which is the main functionality IMHO):

1. Go to the download page and download "KeyJnote-0.10.2-win32.zip".
2. Extract the files in the ZIP archive (using some tool like 7-ZIP) and use folder names, i.e. keep the folder structure.
   You can do that to an arbitrary folder, also on a USB stick.
   So in fact it is a portable application.
3. Now simply drag and drop the PDF file you would like to show on the file keyjnote.exe.
   Then the presentation starts and you can use all the keys described in the documentation under "usage".

In order to use the advanced features (automatic transitions, other sampling, rotation, etc.), you need the command line thing.
If you need the features, maybe someone can help you on your PC. That's kind of hard to explain here.
But if someone can show you, it is certainly quite easy to understand.

KeyJnoteGUI works only under KDE, which is mainly used under Linux systems and is quite hard to adapt to Windows. So this is probably not a suitable solution.

There is one drawback of KeyJnote that I have encountered: If you have many bitmap images in your presentation, starting KeyJnote might take some time, as it resamples the PDF file. So maybe try a small presentation (only few slides) first.

Also the idea of saving to .ppt and use the MS PowerPoint viewer usually works very well!
The only drawback here is that formulas created with the OpenOffice Math component do not convert correctly, whereas with PDF that works fine.

Good luck!
phil

[hommealone]

Again, thanks very much for your help and advise.

I'll try playing around with KeyJnote and see how that works for me. It does sound like an appealing solution. Otherwise I'm sure that one of the other options will serve as a fall-back solution.

Your help was greatly appreciated!

- Paul