I think it is not but my boss doesn't believe me.
Here's some standard code for making a PDF:
Public Function createPDF()
Dim pActiveView As IActiveView
Dim pPixelBoundsEnv As IEnvelope = New Envelope
Dim exportRECT As tagRECT = New tagRECT
Dim iOutputResolution As Integer
Dim iScreenResolution As Integer
Dim hDC As Long
Dim pMxDoc As IMxDocument = My.ArcMap.Application.Document
Dim px1 As IExportPDF = New ExportPDF
Dim px2 As IExportPDF2 = New ExportPDF
Dim px3 As IExportPDF3 = New ExportPDF
Dim pExport As IExport = New ExportPDF
pExport.ExportFileName = "output.pdf"
iScreenResolution = 96
iOutputResolution = 600
'Can some layers be at 300 dpi and others at 600 dpi?
pExport.Resolution = iOutputResolution
.left = 0
.top = 0
.right = pActiveView.ExportFrame.right * (iOutputResolution / iScreenResolution)
.bottom = pActiveView.ExportFrame.bottom * (iOutputResolution / iScreenResolution)
pPixelBoundsEnv.PutCoords(exportRECT.left, exportRECT.top, exportRECT.right, exportRECT.bottom)
pExport.PixelBounds = pPixelBoundsEnv
hDC = pExport.StartExporting
createPDF = 1
Perhaps the purpose can be accomplished with
px1.Compressed (I assume you would want px1.Compressed = true)
px1.ImageCompression = (Adaptive, Deflate, JPEG, LZW, None, RLE)
JPEG is lossy....Obviously with None you get no compression.
LZW is lossless...not sure about Adaptive/Deflate/RLE
px3.JPEGCompressionQuality - how much loss are you willing to tolerate in exchange for smaller file size?
Now any of these would affect your layers equally, no?