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Questions regarding digital canvas size

Hi all,

I'm still relatively new to digital illustration and have a few questions...

Up until now I mostly like to draw concept and character design using pencil and and A3 paper. I'm currently still getting used to my Wacom tablet with Photoshop.

I want to build up an online portfolio, as well as still have the option to print my work in A3.

My question is... Will working on an A3 size canvas in Photoshop (300 dpi) produce good quality A3 prints? And what is the best size to work with for purely online portfolio images? (I assume that I can simply reduce the size of the A3 work to be more suitable for an online portfolio?)



Staff member
If your prints are to be A3 then you're best working at 300dpi at A3 in Photoshop as that's the standard res for print.

For screen then it's usually 72dpi at the size you want it to be seen and I'd imagine this would probably be about A5 and no bigger than A4.

As for retina screens then I'm not sure.


Staff member
If your prints are to be A3 then you're best working at 300dpi at A3 in Photoshop as that's the standard res for print.

For screen then it's usually 72dpi at the size you want it to be seen and I'd imagine this would probably be about A5 and no bigger than A4.

As for retina screens then I'm not sure.
300 may be a magic number thrown about - probably came from prepress monkeys who were following a set criteria set in a preflighting programme.

It does come down to viewing distance - how far you are away from the print etc.

It also comes down to the detail - a foggy scene would look fine printed at 150 ppi. Whereas a face would require upwards of 225 ppi.

It also reliant on printing process, lithographic or digital - and digital is a lot more forgiving, you can probably go about 200 ppi and get away with it.

However, Litho requires a RIP which processes images using LPI - usually Newspapers (more soakage) have a lower LPI, as you don't want to flood the newspaper paper with ink - therefore, the LPI at a RIP would be roughly 80-100 - whereas for a hi-end coffee art magazine thingy it would more than likely be 150-175 LPI (you'd have to ask you printers).

And then the image is converted to halftone dots - here they are rotated to avoid moiré (screen clashes) - the max rotation would be 90 degrees - usually Cyan plate the dots are rotated 15 degrees, M plates, 75 degrees, Y plates 0 degrees,K Plate at 45 degrees.

Because of this - the square halftone dot is rotated at an angle of 45 degrees - stay with me...

Once rotated, a square is exactly 1.41 times it's size

From side to side you can call 1.
The diagonal lines will always be exactly 1.41 times the lenght of the sides.

Therefore, you take the LPI of a RIP - and multiply by 1.41 - most RIPs for lithographic art printing would be set to 175 - therefore it's

And this - and only this is exactly the correct DPI for output on a lithographic printer with a LPI of 175.

And that's why the 300 DPI myth is a myth!


Well-Known Member
Just a heads up, you won't be working in Photoshop at 300dpi, that is dots per inch (printers). You will be working with pixels (pixels per inch) i.e. 300ppi.

The required resolution will depend on what you are drawing, its size and how close (or far) away your drawing will be viewed. For example, a black and white line drawing probably would not need to be 300ppi. That being said, if you were to work at a higher resolution than actually required, there's no real harm done apart from a waste of redundant extra pixels and as a result an unnecessary larger file size. But better to have too many pixels than not enough if you are unsure.


Well-Known Member
As for retina screens then I'm not sure
Again, it all depends on the platform, media etc but I'd say around 144ppi / 140-150ppi in most cases.

There are no real answers, it has to be set up on a case by case basis depending on what you are working on, how detailed it needs to be, its dimensions, so on and so forth...


Staff member
In litho reproduction you'd be required to have line art at 1200 ppi - or higher.

It would be different than for digital.


Staff member
I know the 300dpi thing is a little bit of a myth but just saying what printers usually ask for as standard. ;)

I read before when you posted about this @hankscorpio and I found it really interesting and relevant to an ongoing project I'm involved in.
I did try to find your other post to link to in this one but you know...I couldn't be arsed. ;)

We've been doing a lot of really large format digital art prints recently in the form of canvases and wall papers (kind of) for a high end client.
Some of these suckers are up to 6m x roll width and we've been doing them at 300dpi as specified by the printer.
As you can imagine, multi-layer PSD files at this size are kicking on for 5 GB per section.
These have been killing my MacBook to the point where I've had to be supplied with a pretty high end one just for these.

I remember doing large format at a printers I worked for and the res we used was 150dpi and they looked fine.

I keep saying that we shouldn't need to be doing them at this high-res especially on canvas where the ink tends to spread and blend anyway and running some test prints at a lower res.

Even knocking them down to 250 dpi(ish) would cut the file size down a lot but I still think this is way to high for the medium being used.


Staff member
Nice one Scotty - the couldn't be arsed method is a favourite of mine especially on a Friday!

Yeh you don't need 300 ppi for large format. It's way too overkill for something like that - I've gone as low as 80ppi on these things.

Lithographic printing certainly doesn't require 300 ppi all the time. And certainly not a digital printers.

And the thing with the Newspapers I mentioned, it really depends on substrate, as newspapers are pourous the ink spreads, so you really only need an image that's 120-150 ppi for newspaper reproduction at size of print.

People are too hung up on 300 PPI it's not really essential, not for litho, and certainly not for digital, and certainly not for large format.

However, it does matter when it comes to substrate. If you print 150 ppi on newspaper, it will spread, as newspaper is pourous. You print 150ppi on 170gsm silk - it won't spread, and it will look awful. However, on 80gsm uncoated it might look ok.

Always best to get a sample - I suppose!


Staff member
Thanks for that Hank.

I've been saying that 300 PPI (I say DPI out of habit), especially on canvas is WAY overkill.

I've felt like that little boy in the fable that nobody listened to.
(Maybe that was a tequila and cheese dream...I dunno?)

Thing is, the res thing is a massive issue at these sizes and they are not just banners, they're art prints/digital paintings and the layers and effects combined make the files enormous.
Not only do they kill your machine but it also makes storage and delivery of the files an issue even when flattened.

I think I'm going to arm myself with the info you gave and try to hammer this home.

BTW. Sorry to the OP for highjacking your thread.


There's always been the issue that you can't enlarge raster images without losing loss of quality but I've been recently using some software that's made to counteract this to some extent.

It's called ON1 Resize 10 and I was very dubious about it before we bought it but it's pretty amazing.
It's made for pro photographers to enlarge their pics without losing quality.
I'm not going to say it's perfect but it's the nearest thing I've found that's close.

I've been using it to enlarge some pretty low res vintage newspaper images as we just couldn't get high res as they were quite specific to the project.
It's pretty insane how it works and God knows how it does what it does but it does.


Staff member
Usually just design to scale and the printers RIP has far more advanced scaling techniques. With decent printers of course.

You can upscale, and I've done so in photoshop, using a method I found online. It worked quite well. It was increasing 10% increments, then sharpening to your liking and so on.

Usually upsampling fairs badly. But I've seen RIPs doing far better jobs of scaling on output when increasing percentage size - rather than relying on software.
I almost always do the same: I work with the maximum quality as possible, big canvas in 300 ppi, then, I reduce to the quality that I need for each circustance, so I can use for printing or for my online portfolio without problems.
For me, the question is; How good are you compressing and lowing the size but keeping a razonable quality?
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Thanks for all your answers!

Some of which are very helpful, some of which have confused me even further ;)

If it helps, I mostly like to illustrate high detailed fantasy/sci-fi art.


Staff member
Sorry if I took your thread on a tangent.

I think it boils down to:

If you're printed piece is A3, then work at that size in Photoshop at a minimum of 250ppi (pixels per inch) or 300ppi to please your printer.

When you post it to the web then reduce it to the size you want it to appear and the res of 72ppi should be fine.