How to produce a large 300dpi TiFF print of an iPad sketch

...is the question I've been asking ever since I saw the Hockney exhibition.

So far I have established:

• he uses the Brushes app on his iPad
• Hockney's people state that to avoid pixellation as the size of the print increases, they use a new piece of software which allows prints in a much larger format.

I've looked and looked on the Internet and I can find no mention of the name of the software.  So I asked the question the other way round - the search query was "software used by Hockney to prevent pixelation for large prints of ipad drawings"!

So what's the software?

I'm still not sure - but I've found a suggestion - by a chap called Russ Croop (towards the bottom of the page in the link) - who's a photographer who has been creating large prints from iPhone/Brushes. I've summarised his suggestion below

Brushes Viewer app website - also available as an Apple app

There is a Brushes viewer (the quote is from the Brushes app site)

You can open your .brushes paintings in Brushes Viewer, a free application for Mac OS X. Brushes Viewer allows you to replay your paintings stroke for stroke, export them at very high resolutions (up to 1920 x 2880), and even export them as QuickTime movies.

1. Use Brushes Viewer to export iPad sketch at 5X the native size (using the TIFF format) which produces a large file
2. Import to Photoshop Elements and touch up imperfections (eg unpainted spots)
3. Select Image/Resize/Image Size
4. Unselect resample image box 
5. Type 300 in the resolution box (which changes the file to a higher resolution ie 300dpi which is what is usually required for professional printing) but creates a much smaller image
6. Select resample image box
7. Check you have the units correct for the size of image you want (eg inches or cm)
8. Type in the size of the image you require (eg 20 inches high) - and PS Elements resamples it to create a new large image @300 dpi and keeps the aspect ratio in proportion so long as you also have the "constrain proportions" box checked
9. Also make sure that the Bicubic Smoother is selected (option just below the resample command) as this is the best option when enlarging images.

I tried it - and I now have a very large digital sketch 20x16" in Tiff format sitting on my iMac - which was originally created on my iPad.

I followed all the instructions except for the Brushes viewer bit at the beginning as I already had the digital sketch on my iMac.

Now can anyone improve on that as a method of enlarging digital sketches created on an iPad?

Any queries? Any suggestions?  Any recommendations? 

PS  Two more posts today related to the Hockney Exhibition

• Book review: A Yorkshire Sketchbook by David Hockney on Making A Mark reviews
• Hockney: sketchbooks, iPad sketching and the Yosemite Valley on The Art of the Landscape  This is the post which triggered this post - because I wanted to know how Hockney is creating the very large images from the iPad.