ERROR_BITPERPIXEL (-27 -Invalid bits/pixel) while scanning

I am trying to scan using L_TwainAcquireMulti using Canon LiDE 25 scanner and keep getting ERROR_BITPERPIXEL (errorcode -27) error. Not sure what the problem is, I read on another post it could be due to the fact the bits/pixel of source images could be different from the new image that needs to be saved.

Params passed to L_TwainAcquireMulti:
L_TCHAR *pszBaseFileName = FILENAME.CMP

L_UINT uFlags = 0

L_UINT uTransferMode = LeadTwainLib.LTWAIN_NATIVE_MODE

L_INT nFormat = LEADLib.FileConstants.FILE_LEAD1BIT

L_INT nBitsPerPixel= 1

L_BOOL bMultiPageFile = 0

L_UINT32 uUserBufSize = 0

L_BOOL bUsePreferredBuffer= 1

LTWAINACQUIRECALLBACK pfnCallBack= IntPtr.Zero

L_VOID * pUserData = IntPtr.Zero

What could be possible cause of the error?

Follow up... How do I solve this problem? Preferably not throught LEADLib. Is there a way to change scanner settings?

1. If you use our Fast Twain demo, does it work with the scanner?

2. Which version of LEADTOOLS are you using?

I am using version 13 of LEADTools.

Where do I get the Fast Twain Demo from? Could you point to a place in documentation which describes how to use the Fast Twain Demo?

Thanks

Do you specifically need the Fast Twain features? Fast Twain
is a set of optimization functions that speed up data transfer from high-speed
scanners when acquiring large batches of pages. It is only included in
LEADTOOLS Document Imaging toolkits. The DLL API demo for Fast Twain is in this folder:

LEADTOOLS13\Examples\DLL\FASTTWN

 

If you only want to perform multi-page scanning, you can use the regular Acquire function.

 

If you are using a .NET programming interface, it might be
easier to use the COM objects instead of the C-style DLL API. The regular Twain demos shipped with toolkit are:

LEADTOOLS13\Examples\DLL\Twain (uses the DLL API)

LEADTOOLS13\Examples\COM\VB\TWAIN32 (uses COM Objects).

Thanks I will take a look at these, though the application I am working on provides both kind of features - single page scanning and bulk (multiple page scanning). I am getting error code -27 in both cases.

I also tried using Twacker, and noticed that the value of Capability: ICAP_PIXELTYPE is always TWPT_RGB which is 24 bits/pixel. If I change this value to TWPT_BW & do getCurrent it returns TWPT_BW . But if I close twacker and open it again the value gets reset to TWPT_RGB.

Could this be a limitation of the scanner that it is not able to persist TWAIN capability changes?
Would using L_TwainSetCapability to change the value of capability for a particular scanning session help eliminate error code -27?

It is normal for some Twain drivers not to preserve
capability values between scanning sessions, some of them even resetting values
without closing the application. With some drivers, starting to scan a new page or new group of pages will cause capability values to change.

 

This means you should always explicitly set the capabilities you need before every scan job.

Thanks. I used L_TwainSetCapability to set ICAP_PIXELTYPE to TWPT_BW and it works now.