zooming problem

[shruti]

hello,
m doing the zooming operation on TIFF file with 1 bit per sample...
when m applying the zooming operation on tiff image with
Bit per sample =1
Image Length = 2200 Pixel
Image Width = 1700 Pixel
Resolution(x) = 200 dpi
Resolution(y) = 200 dpi... then it takes 1 sec to complete the zooming.

but when i am applying the same code on tiif image with
Bit per sample =1
Image Length = 3300 Pixel
Image Width = 2500 Pixel
Resolution(x) = 300 dpi
Resolution(y) = 300 dpi..then i takes 8 to 9 sec to comple the zooming
operation.

the code m applyinig is

RenderedImage src= oriRndImage[selectedButtonIndex];(orirndImage is
object of Rendered
Iamge)
//Transfer Current RenderedImage object into BufferedImage object
Raster ra= currRimage.getData(); //it take time.
DataBuffer db = ra.getDataBuffer();
SampleModel sa = ra.getSampleModel();
ColorModel cm = currRimage.getColorModel();
final BufferedImage currImage = new
BufferedImage(cm,Raster.createWritableRaster(sa,db,null), false, new
Hashtable());
//Create new Bufferred Image

BufferedImage bi = new BufferedImage(zoomW,zoomH,
BufferedImage.TYPE_INT_RGB);
Graphics2D g = bi.createGraphics();

double scaleW = (double)(zoomW)/(double)(prev_width);
double scaleH = (double)(zoomH)/(double)(prev_height);
AffineTranform transAtZoom =
AffineTransform.getScaleInstance(scaleW,scaleH);
g.drawRenderedImage(src, transAtZoom);

is there any solution to speed up the large tiff image??
it will be gr8 help for me..if one can give me any suggestion....

Regards,
Shruti.