At the time of writing this, these are the storage capacity for the different iPads
|iPad 8 (2020)||32 - 128GB||US$329 - 429|
|iPad Mini 5 (2019)||64 - 256GB||From US$399 - 549|
|iPad Air 4 (2020)||64 - 256GB||From US$599 - 749|
|iPad Pro 5 (2020)||128GB - 2TB||From US$799 - 2199|
File size for digital art depends on many factors, such as resolution, number of layers, complexity, and even depends on the app itself.
In my case, the total amount of storage taken up by the system files and updates is around 13GB. After deleting unused apps and installing the ones I use, I used up 25GB of storage.
I don't recommend the 32GB storage model to anyone who's thinking of getting an iPad to create art or graphic design. 32GB can fill up very easily and fast.
With Procreate, my file sizes can range from 20MB for simple line sketches (above) to 200-300MB for 4K or A4 300 DPI canvas with multiple layers. If you do the math, in my case, 10GB for 40 (big) to 500 files If you get an iPad with 64GB of storage, that's the approximate number of files you can store, and that's a really rough estimate because file sizes can vary a lot.
If you want to create art professionally, and by that I mean create lots of art to earn money, you'll need at least 128GB storage. This will allow you to create files with higher resolution and more layers (subject to RAM limits).
Note that Procreate would actually record timelapse video of your drawing process by default unless you turn that off in the preferences. Procreate timelapse videos can be lossy or lossless videos and they usually take up around 30-40% of the file size. So if your file is 200MB, the timelapse video can be 80MB. Obviously you can delete the timelapse video to release storage space.
I love the timelapse videos. I find myself sharing the timelapse videos of my drawing process on social media quite often. However, when I no longer need the timelapse videos, I would delete them and they would be gone forever.
For Concepts which is the other app I use very often, the art is in vector format. File sizes even for complex scenes can be less than 10MB. So why not just use Concepts instead of Procreate? Well, different apps for different purposes. E.g. There are certain brushes that Procreate has the Concepts does not. Concepts does not have fill bucket tool. Features are different for both apps. Choose the one that best suit the type of work you create.
10GB of storage can store 1000 Concepts files.
If you're really low on budget, consider cloud storage
As mentioned, I highly recommend getting at least 128GB storage capacity if you can, which will leave you with 115GB before you install any apps or load it up with files.
If you are low on budget, you can consider cloud storage. Yeah, monthly subscription plans.
A 200GB iCloud storage plan cost US$2.99 currently. The next tier is 2TB at US$9.99.
The iCloud plan is considered an essential buy because it will backup your whole iPad including your art. If you create art professionally, you will need backup because you can't afford to lose your work for whatever reasons.
The 200GB iCloud plan will be able backup the whole 128GB iPad and leave you 72GB of online storage. If you run out of space on your iPad, you can transfer your Procreate files over to online storage.
iCloud plan is a must-buy because it backups the iPad automatically. Other online storage providers include Google Drive, Microsoft OneDrive, Dropbox, and more. If you're using Adobe Creative Cloud, you'll have 1TB of online storage too.
For Procreate, when you transfer your files to online storage, sometimes the thumbnails may not show up. So when I transfer Procreate files, I will always create an additional JPEG to serve as a thumbnail. This allows me to see what the art is at a glance by looking at the thumbnail rather than the generic file icon.
Transferring Procreate files to online storage is easy. You can select many files and transfer at one go. And do the same for JPEG thumbnails.
One year of 200GB iCloud will cost US$36.
If you have multiple Apple devices, or have family members that use Apple devices, it may be worth while to get the $9.99/monthly 2TB iCloud plan.
Personally for me, I have Google Drive (US$1.80/mth for 100GB), Microsoft OneDrive ($7/mth for 1TB). I started with using Gmail so I'm kinda stuck with Google. I'm using Microsoft Office apps and the paid version comes with 1TB of storage is plentiful for me to backup my 1TB Mac Mini and store whatever files I need to be online.
So just to sum up, get at least 128GB if you can.