15mb Maximum

Previously I have struggled greatly with squeezing a PDF submission doc down to the required 15mb. So I have spent some time working out a system and it seems to be working quite well.

Assumptions: I’m using Adobe InDesign and Photoshop. Open Source versions of both are available which will work in similar ways.

Step 1: Work out what size your pictures need to be.

It’s best to use pictures that are sized to your presentation. Let’s assume that your presentation is A4 size and Landscape format. That’s 297mm wide by 210mm high. If you have applied margins they need to be accounted for. If your margins are 25mm in all directions, your picture should be no more the 297-25-25 mm in width. That’s 247mm.

If the picture will occupy half the page, it will need to be 125mm wide. To fill 2/3 of the page, 160mm. Obviously, these numbers are dependent on how you are laying out your pages.

Step 2: Resize your image files.

My Canon 6D produces file that are sized at 5472 x 3648 pixels. Expressed as millimetres that’s 463 x 308mm which is vastly oversized for the A4 page of the presentation.

Open the original file in Photoshop and do any editing you want. Save as .psd.

Then click Image on the menu bar and select Image Size. A dialog box opens.

Ensure that resolution is set to 300, units to millimetres and aspect ratio is locked.

Then type in your required width in the width box. Height will be calculated automatically.

Click OK and you have customised the size of the image file.

Now, click File on the menu bar and Export, then Export As.

Format should be .jpg and set quality at 50% and press enter. The size of the file will be previewed on the left of the dialog box. Aim for between 400 and 600 kb for a full page picture, proportionally less for smaller pictures. Click Export and save the exported file wherever you want.

Note that you have exported a file, not permanently changed your .psd file. if you close the .psd it will retain its original quality.

Finally, check the exported .jpg file. If it looks bad, try the progress again, but don’t reduce the quality as much.

Step 3: Saving the presentation.

Insert the images and text into your presentation and save at full quality in the native format for the application. For InDesign, that is .indd.

To create a PDF, click File on the menubar then Export. Select where you will save the PDF and give it a name. Click Save.

The Export Adobe PDF dialog will appear.

On the General tab, Adobe PDF preset setting, select High Quality Print.

Change to the Compression tab and set Image Quality to High. Click Export and your PDF will be created.

I have added about half the content of my PDF, which includes 14 pictures, some at full page over 14 pages. File size is 5.6mb and the pictures look good. So I’m on target for the final product to be less than 15mb.

I hope you find this useful.