// Javascript copyright Sean T. McHugh
// Cambridge in Colour Photography
// http://www.cambridgeincolour.com

<!-- Begin Sharpening Calculator
function doField(form) {
view_dist = form.view_dist.value;
print_res = form.print_res.value;

if (isNaN(print_res)) {
	alert('Please enter a numerical value for the PPI print resolution.');
	document.form.print_size.focus();
	document.form.print_size.select();
	}

else {
radius = view_dist * print_res * 0.0004 / 2.54;
form.radius.value = Math.round(10 * radius) / 10 + " pixels";
	}
}
//  End Sharpening Calculator -->

<!-- Begin Enlargement Calculator
function doField0(form0) {
view_dist2 = form0.view_dist2.value; //in cm
eyesight = form0.eyesight.value;
aspect = form0.aspect.value;
megapixels = form0.megapixels.value;

if (isNaN(megapixels)) {
	alert('Please enter a numerical value for the megapixel resolution.');
	document.form0.print_size.focus();
	document.form0.print_size.select();
	}
else {
longpixnum = Math.sqrt(aspect * megapixels * 1e6);
maxpixwidth = 0.000290888 * view_dist2; //in cm per pixel
max_dim = eyesight * maxpixwidth * longpixnum / 2.54; //in inches
min_ppi = eyesight * 2.54 / maxpixwidth; //in pixels per inch
form0.max_dim.value = Math.round(10 * max_dim) / 10 + " inches";
form0.min_ppi.value = Math.round(10 * min_ppi) / 10 ;
	}
}
//  End Enlargement Calculator -->