Increasing Resolution 1

[MorganChai]

I have a simple, small black and white graphic that is currently at 150 dpi. I need to boost it to 1,200 dpi. How do I do it?
Thanks. Morgan

 

[slickyboi]

In Photoshop go to Image\Image Size.. you can increase your resolution in there

 

[duncdude]

this will require a 64 x increase in resolution - 150 dpi -> 1200 dpi (8 x) both width & height = 8 x 8. This is alot of interpolation, i.e. inventing of data. You might try making it greyscale after being enlarged, then a small amount of gaussian blur to reduce the 'stepping' then back to black & white again. This is the trick I use.

Duncan

 

[Eggles]

It is totally unrealistic to think you can increase the resolution of a 150dpi graphic to 1200dpi and not end up with a complete blurry mess.

The pixels to be added have to be conjured up by sampling the nearest neighbour, and with only 150dpi, there aren't too many neighbours. You would end up with more guessed pixels than original pixels. Either rescan or rephotograph the original image if possible, otherwise you will be very disappointed.

 

[mscallisto]

MorganChai

I tend to agree with Eggles, if you're working with a scanned image at 150 dpi and blow it up that much you most likely will end up with a mess. Can you re-scan?

Duncdude

I'm interrested in your trick but don't quite understand it.

"You might try making it greyscale after being enlarged, then a small amount of gaussian blur to reduce the 'stepping' then back to black & white again".

Can you explain what's happening here?

 

[duncdude]

by making the picture 'greyscale' you can apply a gaussian blur to the picture. this will soften the stepped lines and when converted back to black & white you will get a far nicer result. it will, however, reduce the accuracy of the original.

Duncan

 

[ticke]

you can increase resolution the way you describe and not lose any details by clicking off resampling image. Then again, you end up with a tiny picture.

Good luck to ya..

 

[mscallisto]

Thanks Duncan that may come in usefull

 

[Eggles]

>>you can increase resolution the way you describe and not lose any details by clicking off resampling image. Then again, you end up with a tiny picture<<.

Yup.