High Resolution Effects...

[Taborious]

Question for any Photoshop guru, if I change my image from 300dpi to 150dpi will that change my layout when printing? I know it will affect the resolution but I printed a rough draft of the control layout in black&white and drilled and routed the CP. So if I change the dpi now will it affect the location of my buttons and joysticks as it relates to the rough draft print?

[oldsage]

I am 99% sure, but i don't want to mislead you... There is no reason it would change stuffs size, only the quality of the printed art...

[Pixelhugger]

I can't imagine it would affect anything other than the quality... at least it shouldn't, provided it's done properly. Make sure you have resample image checked in the image size dialog box or it will scale the picture's physical size... IE it will keep the same number of total pixels.. spreading them across a larger area. Experiment with the option checked and unchecked to see what happens to the size in inches and you'll see what I mean. If you do not resample, when you change the dpi from 300 to 150 it will double the image dimension in inches. Make sense?

[markrvp]

As long as the Document Size Width & Height values don't change, the printout size will be exactly the same, just at a lower resolution.

[Taborious]

What do the different resampling selections do "Bicubic" what is that exactly???

[Pixelhugger]

From my understanding bicubic and bilinear, etc. refer to the number of pixels taken into account around a given pixel when reconstructing or changing an image. You can think of it like a grid that is used to rebuild a new image, similar to compression.

If for example the application is going to reconstruct an image at a smaller size (using fewer pixels) it examines the data to determine what will be thrown out, what will be left, and what will be averaged. So say you have a blue pixel surrounded top bottom left and right by red pixels which in turn are sitting in a field of white. The resampling mode determines if the app looks only at the blue pixel and what is immediately next to it, or whether it looks beyond to the pixels surrounding the red ones as well. This will determine if the reconstructed image contains a single purple pixel as a result, or a purplish blue pixel with some bluish pink antialiased pixels around it etc. Chances are the different results will be too subtle to really notice. I always leave it checked to the default. 

[mahuti]

The default is best for most applications. If you want to scale up a sprite/bitmap and leave the jagged edges, you'll want to scale up in multiples of 4 using "nearest neighbor," otherwise, PS will antialias everything making it smooth.

[markrvp]

In Photography, we always use Bicubic.  In Photoshop CS, two new methods were added:  Bicubic Smoother, and Bicubic Sharper.  If you are upsampling an image greater than 50%, then I get better results with Bicubic Smoother.  If you are downsampling quite a bit, then sometimes Bicubic Sharper works well, but not always.  Many times when downsampling, I use Bicubic and then do an Unsharp Mask at 50% with a radius of .5.

For whatever that's worth

[Taborious]

wow, a lot of information, but good stuff. I have another question regarding the filters and resolution. When you create an image say 600x600 72dpi and use the wind effect to make wind marks as we all now. Now for a larger CPO image 34in X 19in 300dpi or so you run the same wind effect it has practically no affect on the image. Is there anyway to adjust the overall effects intensity if it isn't included on the effect popup window. Alot of the cool effects Ive seen you have to create on a small image and then scale it for the CPO and that affects quality....

[Taborious]

anyone know if there is anything that can be done with high res effects? Just trying to give the thread another look before I let it die...