C41 Films & CD pixellation?

[mike goldberg]

Hi... I'm using Superior 200 [C41 process], and my favorite 1-hour photo shop scans at 300 dpi; most frames are between 1 - 1.5MB.

THE PROBLEM:
Until I resize the image to 1024 x 768 or 800 x 600 pixels [72 dpi for Web], there is intense pixellation... making the negs look like they were developed in 'duck soup.' Can someone explain this phenomenon?

I know intuitively that it's got something to do with the Analog/Digital conversion.

Further, it is likely that the photo shop uses a Nikon scanner with a point light source, which is harsher than a flourescent, diffuse light source.

FEEDBACK WELCOME.
Thanks, mike

 

[kbg32]

300 dpi @ 1 -1.5 mb are quite small file sizes. Any up-resing will result in the images looking pixelized. If you lab can, have them rescan your negs at 300 dpi, 17" on the long side and let the short side fall where it may. It might cost you more, but the file sthey are supplying are pretty small.

 

[mike goldberg]

Hi Keith,
That was fast! I kinda thought so...
Will try larger file sizes in the CD scans, next time around.
Thanks, mike

 

[40oz]

if they are scanning negatives, 300dpi at the scanner will look like crap. If you then resize to 800x600 or 1024x768, you are basically just increasing the size of each pixel. Depending on the resampling method, each "new" pixel is a guess at what color it ought to be. You need to scan at the least size you wish to display. So if you want 1024x768 or so, you need to scan for that final resolution, around 800dpi. 800x600 would be roughly 600dpi.

Something to keep in mind is that browsers will display at 100%, dpi has no meaning. I you want an image to display at 1024x768 in a browser window, you need to size the picture at 1024x768. Given a negative that is 1 inch on the short side, to get 1024x768 you would need to scan at 768dpi to get 768 pixels on the short side.

 

[venchka]

That's strange. My garden variety scans are 1818x1228. I output from Lightroom at 900 on the long side @ 72 dpi and they look ok.