Sorry for the confusion Jim. I meant non-linear when I see the mask close at 1. And yes I use MLT for non-linear also. I will use the Starlet algorithm. MLT is the replacement for ATWT which is now depreciated. MLT added the linear mask and linear algorithm. There is no need to use ATWT that I can see. I use MMT late in processing more for high contrast images. In the past I would use ACDNR. I do wish the mask function had finer control when using it with non-linear images. That is one of the things that makes ACDNR so strong is it's great mask feature. That being said a value of 1 or 2 generally works well from the linear mask. A value of 1 with the linear mask is basically like making a clone of the image.
Here is a quote from Juan on MLT and MMT from a posting last April
http://pixinsight.com/forum/index.php?topic=6972.0* The new MultiscaleLinearTransform (MLT) tool replaces ATrousWaveletTransform (which is now deprecated but maintained for compatibility). MLT introduces a new linear multiscale transform based on multiple Gaussian filters, besides the starlet transform (aka à trous wavelet transform).
* The MultiscaleMedianTransform (MMT) tool introduces a new median-wavelet transform that splits the multiscale representation optimally into wavelets for nonsignificant structures and the median transform for high-contrast structures.
* New linear mask feature integrated in the MLT and MMT tools. Linear masks greatly enhance noise reduction of raw linear images.
Mike