I've got a Photoshop CS2 file with two layers, the top one is a modification
of the bottom and the blending mode is Dissolve with moderate opacity. This
produces the very grainy, almost dirty effect I wanted. When I either try
to merge the two layers or flatten the image, the entire Dissolve-effect is
lost and the image appearance changes radically.

A) What am I doing wrong?

B) How should I create a single layer that encapsulates the Dissolve effects
of the two layers?

TIA
Norm

"Norm Dresner" <ndrez@att.net> wrote in message
news:3ZVEj.30124$D_3.29504@bgtnsc05-news.ops.worldnet.att.net...
> I've got a Photoshop CS2 file with two layers, the top one is a
> modification
> of the bottom and the blending mode is Dissolve with moderate opacity.
> This
> produces the very grainy, almost dirty effect I wanted. When I either try
> to merge the two layers or flatten the image, the entire Dissolve-effect
> is
> lost and the image appearance changes radically.
>
> A) What am I doing wrong?
>
> B) How should I create a single layer that encapsulates the Dissolve
> effects
> of the two layers?

Hi Norm,

The grainy effect you're seeing is almost certainly due to the approximate
mathematics behind Photoshop's preview resampling. Zoom the image to 100
percent to get an accurate preview of the merged layers.

--
Mike Russell - www.curvemeister.com

On Mar 21, 4:42 pm, "Norm Dresner" <nd...@att.net> wrote:
> I've got a Photoshop CS2 file with two layers, the top one is a modification
> of the bottom and the blending mode is Dissolve with moderate opacity. This
> produces the very grainy, almost dirty effect I wanted. When I either try
> to merge the two layers or flatten the image, the entire Dissolve-effect is
> lost and the image appearance changes radically.
>
> A) What am I doing wrong?
>
> B) How should I create a single layer that encapsulates the Dissolve effects
> of the two layers?
>
> TIA
> Norm

If Mike is correct you might take a look at menu - Filter>Add Noise.

On Mar 21, 7:32 pm, "ronvi...@gmail.com" <ronvi...@gmail.com> wrote:
> On Mar 21, 4:42 pm, "Norm Dresner" <nd...@att.net> wrote:
>
> > I've got a Photoshop CS2 file with two layers, the top one is a modification
> > of the bottom and the blending mode is Dissolve with moderate opacity. This
> > produces the very grainy, almost dirty effect I wanted. When I either try
> > to merge the two layers or flatten the image, the entire Dissolve-effect is
> > lost and the image appearance changes radically.
>
> > A) What am I doing wrong?
>
> > B) How should I create a single layer that encapsulates the Dissolve effects
> > of the two layers?
>
> > TIA
> > Norm
>
> If Mike is correct you might take a look at menu - Filter>Add Noise.

Filter>Noise>Add Noise

On Fri, 21 Mar 2008 22:42:36 GMT, "Mike Russell"
<RE-MOVEmike@Curvemeister.comRE-MOVE> wrote:

>"Norm Dresner" <ndrez@att.net> wrote in message
>news:3ZVEj.30124$D_3.29504@bgtnsc05-news.ops.worldnet.att.net...
>> I've got a Photoshop CS2 file with two layers, the top one is a
>> modification
>> of the bottom and the blending mode is Dissolve with moderate opacity.
>> This
>> produces the very grainy, almost dirty effect I wanted. When I either try
>> to merge the two layers or flatten the image, the entire Dissolve-effect
>> is
>> lost and the image appearance changes radically.
>>
>> A) What am I doing wrong?
>>
>> B) How should I create a single layer that encapsulates the Dissolve
>> effects
>> of the two layers?
>
>Hi Norm,
>
>The grainy effect you're seeing is almost certainly due to the approximate
>mathematics behind Photoshop's preview resampling. Zoom the image to 100
>percent to get an accurate preview of the merged layers.


On the other hand Norm, Why don't you simply save it as a TIF without
flattening it. Then you would have a single layer displaying what you
want.

Dave

"Mike Russell" <RE-MOVEmike@Curvemeister.comRE-MOVE> wrote in message
news:wRWEj.15928$5K1.12404@newssvr12.news.prodigy. net...
| "Norm Dresner" <ndrez@att.net> wrote in message
| news:3ZVEj.30124$D_3.29504@bgtnsc05-news.ops.worldnet.att.net...
| > I've got a Photoshop CS2 file with two layers, the top one is a
| > modification
| > of the bottom and the blending mode is Dissolve with moderate opacity.
| > This
| > produces the very grainy, almost dirty effect I wanted. When I either
try
| > to merge the two layers or flatten the image, the entire Dissolve-effect
| > is
| > lost and the image appearance changes radically.
| >
| > A) What am I doing wrong?
| >
| > B) How should I create a single layer that encapsulates the Dissolve
| > effects
| > of the two layers?
|
| Hi Norm,
|
| The grainy effect you're seeing is almost certainly due to the approximate
| mathematics behind Photoshop's preview resampling. Zoom the image to 100
| percent to get an accurate preview of the merged layers.
|
| --
| Mike Russell - www.curvemeister.com
|

Absolutely! I zoomed in on a very small area and then flattened the image
and there was absolutely no difference in the pixels I could see at that
level. I suppose I should have guessed this when a previous experiment
showed that the effect was dependent on the size of the image -- doing the
same thing with a very small image produced no effect.

SO ... Let's see ... The images that Photoshop presents on the screen are
all approximate because they have to be sampled at the screen resolution --
which in my case is 1920x1440 or about 128 PPI. But when I print, the
resolution is (usually) 300 PPI. Does that mean that I can zoom to, say, 3x
the Fit-On-Screen magnification and see what the actual pixels that will be
laid down on the paper would look like? Your 100% recommendation is ~4.5x
the F-O-S magnification of 22.5%.

TIA
Norm

"Norm Dresner" <ndrez@att.net> wrote in message
news:aQ7Fj.32131$D_3.6247@bgtnsc05-news.ops.worldnet.att.net...
[re Photoshop preview resampling inaccuracies]

> Absolutely! I zoomed in on a very small area and then flattened the
> image
> and there was absolutely no difference in the pixels I could see at that
> level. I suppose I should have guessed this when a previous experiment
> showed that the effect was dependent on the size of the image -- doing the
> same thing with a very small image produced no effect.

There are a number of effects that preview differently, depending on the
zoom. These are fairly rare, though, so it's not unusual for people to be
surprised when it happens.

> SO ... Let's see ... The images that Photoshop presents on the screen are
> all approximate because they have to be sampled at the screen
> resolution --
> which in my case is 1920x1440 or about 128 PPI. But when I print, the
> resolution is (usually) 300 PPI. Does that mean that I can zoom to, say,
> 3x
> the Fit-On-Screen magnification and see what the actual pixels that will
> be
> laid down on the paper would look like? Your 100% recommendation is
> ~4.5x
> the F-O-S magnification of 22.5%.

My recommendation would be to flatten the image temporarily, then set the
zoom to match the print size.

When you view a zoomed out preview, Photoshop saves time by resampling
first, then flattening. When you print, Photoshop does it in the opposite
order: flattens first, then resamples to the resolution required by the
printer driver.

For most images, this makes no earthly difference. A layer with a dithered
bitmap image is a common case where this can matter. As a practical matter,
if the appearance is not what you expect, 100% zoom is the most accurate
preview. If you don't want to zoom to 100 percent, flattening the image
also gets a better preview.
--
Mike Russell - www.curvemeister.com