I use adobe lightroom. It has an enhanced algorithm that really does a very good job at upscaling images. You might also try https://imglarger.com/. Source: over 1 year ago

But this time I just googled and ended up with https://imglarger.com/ that did the job well. Source: over 1 year ago

I don't, but try imglarger.com, it's A.I. That scales up an image, I always get amazing results. Source: almost 2 years ago

Hey, this picture looks so cooool!! I save your original image and upload it to imglarger.com to sharpen it. Here is the result. I am not sure if it is what you want. But I think the the color and contrast is better after the image is sharpened by imglarger. Source: about 2 years ago

Image was upscaled with imglarger.com as Dall.E's output images are way too small. Source: about 2 years ago

If the camera they used for scanning has a small sensor and noisy gain, that would introduce a lot of noise. The film itself will have noise, depending the iso and brand of the film. If the blacks details weren’t squashed, post editing using Neat filtering can literally work a miracle. It works similar to a temporal noise filter but has much higher intelligence built in. Check out Neat Filter sample. Source: about 2 years ago