Re sizing a image with out loosing resolution

[Rchjr]

Hi everybody,

I have drone video that was shot in 4k, I have to pull some stills out of it and have it re sized to 851 x 315 and 900 x 300. What is the best way to resize the iamges with out loosing resolution?

Thanks,

Rchjr

[Mylenium · Accepted solution]

There is no such thing. You will of course lose information since data gets interpolated. There are ways to minimize the loss of information by employing adjustments and effects just as well as doing the resizing in multiple steps to control specific aspects, but reducing a 4k shot to 10% of its size is always going to look like a crappy webcam photo, no matter what.

Mylenium

[NB, colourmanagement net]

Not sure I am understanding

- you wrote "re sized to 851 x 315 and 900 x 300"

Are you wanting to downsize [downsample] 4K to 851 x 315 and 900 x 300??

If the image is 4K: 3840 × 2160 pixels and you downsize to 851 x 315 and 900 x 300 pixels, then you are inevitably discarding a LOT of pixels.

SO it's not possible to do this without losing resolution [which is normally expressed as pixels per inch]

OR are you wanting to make crops from the 4K master image at 851 x 315 and 900 x 300

- then size that up 4K (3840 × 2160).

That upsizing process inevitably "creates" a lot of pixels. 

You can't create pure resolution in upsizing.

To give a file more pixels [higher resolution in dots per inch or cm], the neighboring pixels are sampled and may be duplicated.

Photoshop's upsizing algorithm is pretty good - you'll need to experiment.

Some say that sizing up in steps adding a little sharpness at each is a superior way, it's going to be image dependent. 

I hope this helps
neil barstow, colourmanagement net :: adobe forum volunteer:: co-author: 'getting colour right'
google me "neil barstow colourmanagement" for lots of free articles on colour management

[Earth Oliver]

Neil, this post is from 2017...

[NB, colourmanagement net]

How strange that it came to my attention, maybe it popped up on the right side in "posts on similar subjects", plainly I need to be more alert!

thanks