Illustrator Tracing big vs small image

[pashkatarakashka]

I have a pen sketch scanned with resolution ~ 7000x5000px 300DPI. When I'm trying to trace the whole image with Illustrator CS6 into b/w, I am losing details overall. Example is on the left side. It's just part of the image.

However, when I tried to isolate a couple small raster pictures from the big one and trace them separately, I got pretty good results comparing to tracing a whole picture. The isolated images are with resolution ~700x800px 300DPI.
The problem is that I can't isolate all elements in sketch then combine after tracing, it's hell lot of work. So my hope is that there is some technique of tracing big images.

 

[hawkeye]

Try adjusting the advanced settings in the Image Trace panel if you have not done so yet.

 

[pashkatarakashka]

Try adjusting the advanced settings in the Image Trace panel if you have not done so yet.

I have done that. I want to understand why tracing big and small images so different.

 

[Paul]

Self explanatory really.

 

[Tom Mann]

In both cases, when you stroked the paths generated by Image Trace, are you sure you used the same width settings? The two widths look very different.

T

 

[pashkatarakashka]

In both cases, when you stroked the paths generated by Image Trace, are you sure you used the same width settings? The two widths look very different.

T

I'm not sure which width you mean, but if it's stroke width in Tracing advanced options, then yes, both have the stroke size same. I also tried to completely turn off stroke, not much help.

I think Illustrator tracing engine is first analyzing the whole image, then defining internally some average width of tracing. I tried different software and got much better result for whole image.