exporting maps from PS

[Andarr]

Hello to all mapmakers.

I have a question for those who use Photoshop as main mapmaking software.

I am usually drawing on 300dpi on a format A3 (sometimes smaller, sometimes bigger) and when i am finished i save the result as PNG. The problem is that mainly when i am dealing with coloured map, i end up with pretty big PNG file. Even when i am using the lowest file size setting during the export.

I am not sure now but i think that in the past i tried to flatten the image before save but it did not helped.

How do you save your finished maps? Do you take the big file, and downgrade the resolution for web preview or do you have some tips?

Thanks in advance for anything related to this issue.

[TimetoDraw]

Hi Andarr

I tend to work in 300dpi and A3 as well. In order to post something to the forum (or host on my webserver), I normally shrink it down to A4 size or smaller before saving to PNG. So you don't accidentally save your source file as A4, maybe save a separate version to shrink down to A4.

Others may have a more efficient method?

[Redrobes]

The usual way to do it is to save the map that you are working on and want to continue to work on in the apps native format. Then for putting a copy up on this website for example you flatten it, scale it so that it is something like 2000 pixels wide and then save it out as a png or jpg depending on whether it has lots of solid colour with thin lines or is more of an artistic or photo map.

The PNG format is lossless so that it does not compress as well as JPG. But PNG is better where there is a lot of solid colour like charts, graphs and similar or when you really need to keep the detail exact, or where you are in need of saving tokens where it has a transparent background. In that final case use the 32 bit format which is RGBA and A is alpha which is a value of transparency.

If you are using a paint app that does not have a native format then PNG is best to keep it lossless. But I don't think photoshop lacks a native format. The native format has the ability to hold more information such as the layers, settings and other attributes that a normal image format will not.

When you want to work on your project again then load up the original file not the flattened scaled one.

Also, whilst I am here. Save your working file is MyProjectName_01, MyProjectName_02, MyProjectName_03 etc as you keep making changes. If you keep saving it over and on top of the same file then if anything goes wrong with the save, or the file gets corrupt or that you decide that the latest change you made is no good then you have the ability to go back and work from an older copy. Once your totally finished with the map then back up the final copy to a few hard drives and then you can delete all of those intermediates. And its best to back up that final copy to a (or several) USB external drive and not to put the backup copy on the same hard drive as the primary copy.

You may find my tutorial on technical side of bitmaps a useful read.

https://www.cartographersguild.com/s...ead.php?t=2596

[Kellerica]

Red covered the bases pretty well. I concur with all of what he said.

As Red pointed out, PNG is a lossless file format, so with that you do end up with big file sizes pretty easily. I usually prefer to save my work as a JPEG for later viewing. The compression is noticeable, but it usually serves to show the work in enough detail that it's worth it for the smoother viewing experience. There are times when you do need a more high quality file, but in most cases JPEG's serve me perfectly well.

[Andarr]

Thanks guys for your intel.

I will check Redrobes thread which he posted and surly will take your advices.