How to upscale for 10 foot tall poster with only 5000 px images!?

Just as a final note; the article linked below is a good one for explaining resolution VS viewing distance. I keep it bookmarked.

What print resolution works for what viewing distance?

--OB

Dave is spot on.

I'll just add my own rule of thumb. Print it out and pin it on the wall:

If it works for a magazine spread, it will work for a wall-sized banner or a roadside billboard.

Don't upsample unless it's absolutely necessary - which it probably isn't here.

Hi Bob, or do you prefer unicycle?

What is the poster's content?  If it is not simple a raster photograph, but has vector contend like text and graphics, then they will obviously print perfectly sharp, and IME that tends to pull the scene together.  The eye has sharp lines to lock on to, and does not worry about a pixelated image behind the graphic content.

You can try some  sharpening processes  to improved the upressed image.  It is a great pity that Jeff Schewe's The Art of the UpRes has completely disappeared  from the internet.  Jeff is  world expert on this stuff, and still has lots of useful information online.

https://forum.luminous-landscape.com/index.php?topic=76058.0

jeff schewe - YouTube

The way Michelle scales the image works good for me too. I use 110% to avoid distortion and have recorded this in an Action. This way you only have to push the button in the Actions panel to repeat the scaling. 

I have had really good results by using the Image Size command (Cmd-Option-I), setting the drop down menu next to the Width and Height to Percent and using a value of 150%. I will then repeat it until I get the desired height or width.

I agree with the suggestion above, that the first thing you should do is talk with whoever will be printing this for you to see what resolution they need. If it is a video wall, the resolution will be a fixed number and not a multiple of pixels per inch. It's always important to know the end goal of your resolution when you start.

you can get away with a pretty good amount of upscaling in Photoshop. But it only goes so far before it will start to look bad. And as Michael stated, you can also use a lower resolution to some extent for larger prints because of the distance away the viewer will need to be to see it right. OnOne used to make a product called Genuine Fractals that did an amazing job of enlarging images up to the size of billboards. It took a while to render that stuff out, but the final product was pretty darn good. You might want to look into that.

Hi Rob,

The main question here is what resolution do you need. We are used to printing things like brochures at 300dpi. However, for things that are viewed at a distance we can get away with far lower resolutions. This is great because it means we can scale our images to much larger sizes. Talk to the people who will be printing this for you and ask them to guide you on the minimum resolution required.

You might also find yourself asked by the printer to prepare a high resolution file but one that is smaller than the print size. One place that printed a bunch of pull up banners for me had me prepare high quality files that were only a quarter of the size. The files were small enough to transfer and they would then scale them up at their end for printing.

Cheers,

Michael