It is strange that increasing the Nor slider or increasing color contrast of the normal texture DON’T affect the intensity of the normal map.
The only way I can think of is to duplicate the normal texture slot, so that the normal effect will be doubled. What is your solution, I love to hear the others’ ideas (I dont like adjust the normal map strength in GIMP, I want to do it right in Blender)
Haven’t used 2.4 series in a while, but try using the NoRGB option. That might work in conjunction with the in-texture contrast controls. Otherwise, you’re going to have to (unfortunately) go into the image file with an Image editor.
should go with 2.5 much more control over the normal value then in 2.49!
and gives also better resutls
but don’t import it from 2.49 or will have to change the algo to 2.5
which is difficult to find
create this in 2.5 and it will use the new bump algo for 2.5 not the old one form 2,49!
salutations
Thank you two, unfortunately, I have tried your solutions and none of them affects the normal intensity 
If you were in my situation, what would you do ?
normal and bump maps normally have a small 3D effect!
for bigger effect you might need to go with displacement modifier!
see wiki on this subject !
but it’s more difficault to use then with normal or bump map !
happy 2.5
Can you post your normal map image?
Ooooo! Just remembered this: Object scale can affect normal map appearance. Try this (not sure which way it works): scale your object down by a factor of 10 (Scale: 0.1) in object mode. Now, go into Edit mode, select all and scale the mesh up 10x. You end up with an object of the same apparent size, but a Scale object value of 0.1. Now render. The map should look different.
Note that this might be backwards and you should GROW you object in object mode, then SHRINK it back in Edit mode. Not sure. It’s been a while since I’ve done it.
What do you mean exactly about Normal intensity? I use this all the time to great effect. That is, increasing the value.
Can you post an image of what you want or an image of what you are doing?
There are other things that can affect the normal value as far as appearance goes. One is the relevant angle from the camera to the surface and to the light source. The closer to the angle of the light the surface angle is, the less bump.
Take a practical example. You have a bump map on the floor. You light the subject from above and there is not much of a bump map on the ground because of the angle of the light. So you put the character in another layer and make the light illuminate the character only. Then in the floor layer you shine a light at an angle lower to the floor across the floor to pick up the bump.
There are size issues as well. You can adjust that in the texture itself and the mapping area. If the texture is too small or too large, you can have an image that has little apparent value depending on the texture pattern.
Then the shading and specular also can play a role.
If you’re talking about a real Normal Map, then changing the contrast won’t have any effect, and the Nor-slider will reach its max at 1 or -1. I believe that’s just how Normal Maps work.
Using bump maps or height maps is a different thing; changing the Contrast and Nor-slider beyond 1 should make a difference.
Using multiple textures should be the way if you wish to increase the Normal Map effect
Excuse me. Before coming to Blender, “Normal Maps” have always been that, and Bump Maps another thing entirely. However in Blender when you use a bump map, you map it to the normal channel and there is no bump channel. This was very confusing to me at first and after some time I have been corrupted by Blender speak - as far as the interface is concerned.
So forgive me I was talking about Bump Maps. Gray ccale images. Thank you Sago for the clarification. I read Normal and was just assuming bump.
dont forget as indictead in wiki that normal map works well when in same angle with camera to get max 3D effect
but sideways it does not work well
bump map works better
also 2.5 has better algo and better effect then in 2.49!
i’d like some sample files showing the difference here between bump and normal map
anybody knows a wiki page demosntrating the difference here or other site may be!
thanks happy 2.5
Thank everyone for taking your time, here are some images that show what I want to achieve, the normal map and the effect I get when using it once, twice, 3 times. That is what I mean intensity, I think it’s cool, the default effect is quite weak.
After duplicating it several times, I bake to have a new, stronger map. It will be better if we can use a slider to control the normal strength.
harkyman, I tried your method and … the effects are the same 
It doesn´t really matter how you scale your object.
A normal map has one pixel with the 3 colors RGB.
each color channel is used to store the XYZ values of a vector.
This vector is the normal vector for the underlaying “surface” while this surface is virtual.
From this normalvector the tangent space gets calculated, which is pretty much the plane in which the geometry beneath would lay.
What happens during rendering is that for the shading with the light vector the dot product of this normal vector is calculated against the light, faking geometry.
The thing is, a Vector within a normal map is normalized. This means that the XYZ values of the vector are re-calculated so that the vectors orientation remains the same, but its resulting lenght is 1.
So you can´t really scale the values in the normalmap as the lighting would go bonkers when doing the calculations with non-normalized vectors, and if you lets say shrink the blue value, which represents the Z value of the normalvector the vector would get flatter and the underlaying geometry would seem deeper, however the G and B values would not match anymore to have a normalized vector.
I am certain there are tools to depthen a normalmap and re-normalize it, I am not sure though if blender can do it on the fly, meaning to change the values in memory and renormalize the normalmap without touching the normalmap.
If I am not completely off track the contrast of the normal map should change its overall depth.
Try to play with the contrast of the normal map in gimp but don´t use any color corrections, just the contrast and see what happens =)
EDIT:
Yeh just tried it. High contrast = deep, lower contrast = flat.
The slider in blender only affects the normal map from -1 to +1 which seems to turn the normal vectors by 180° so you can make an existing normal map flatter, even reverse it, make it indent instead of bevel, but the maximum depth information is absolut and rigid.
It is the nature of normal maps.
If you got no idea what I wrote about and want to know more I can draw some explainatory sketches.
So how is it that Blender deals with a Normal map and a Gray scale map in the same channel? That’s something I don’t get. I am not sure how they handle that internally. Generally I think Blenders normal/bump mapping is weak. Not much range.
But that said, the slider in 2.5 goes to 5 and I was able to load a normal map in and get some decent intensity. But to bring it to the level in the 3rd test above, I could not do that. Multiple instances might just be the way to go.
Thank you, arexma, very clever explaination. Modifying the normal map in GIMP to increase the normal strength is what I already knew. I just want to know if anyone can do it right in Blender (because personally I don’t like GIMP due to its multiple and floating windows), and finally the answer is NO WAY.
Thank everyone again.
[ATTACH=CONFIG]121551[/ATTACH]if i remember well you can go higher then 5 for normal in 2.5
but been a long time and don’t remember well what’s the max here!
i’ll try to make a test and be back
see pic
first one is with NOR =29 second one on th right NOR =5
still don’t know what the max is ?
salutations
